I've planned a tour starting in Florence, Italy to Bern, Switzerland (touring plans here) leaving on May 10. Before then, I have family obligations in the UK and 10 days with the wife in Tuscany with very little chance for any bike riding. I have been training hard and am in bike touring shape. But, I've never gone a month of little to no bike riding before starting out on tour.

How long have you gone between training and touring? Did the lay-off cause any problems?

I purposely have a couple short days to start the tour, though north of Florence is quite hilly, so even short days will be a bit challenging.

As long as you are somewhat "active" and don't eat/drink too much, the time off should not dramatically decrease your performance. After three to four days in the saddle, you will start to feel like yourself again. The key is not to treat the time off as though it is Christmas.

I have taken 3 weeks off for a beach trip and did not have much issue. That included some swimming, beach walks, and eating somewhat healthy.
On the other hand, I have taken 2 weeks off during the holidays (big meals, desert, and beer!) and when I got back on the bike I felt like a pudge...

I expect part of the answer may be age related.

I have always been active and riding my bike anyways, so there hasn't been as much of an explicit "training" phase. The past 18 years I haven't owned an automobile and have lived in places (CO, OR, TX) where I've been fortunate to bike to work, errands and otherwise use my bike as a primary vehicle. Prior to that I did live in places (e.g. MA) where the roads were icy enough that I would do most my commuting in the months with daylight savings and drive to work over the winter months. So there was an occasion or two when I wouldn't have bicycled for a month+ - and then flew to a warm destination for a winter bike trip. I was younger and also active so it wasn't a big deal.

I suspect this varies significantly by individual, so bear in mind relative to my following comment.

Back when I was bicycling >25 miles a day 5-6 days per week, I definitely noticed a decline/loss of fitness after only a one week break. It was not like starting over from nothing, but I think my pace/time was down 10-20% from taking a week off, and required another week or so of bicycling to recover and get back up to speed. I think your concern about a month-long break is certainly valid. If there's nothing you can do about it (substitute walking/running), then there's no point in worrying. Try to not gain weight during the break, since it'll probably make the situation worse.

Ive certainly gone out of my way to keep cycling before a trip, even to the point of riding in winter to keep the legs moving.
The times I have gone 3 weeks or whatever before riding, its been tough to a certain extent, especially with one of my knees that can be cantankerous ,and so I figure the wisest thing would be to plan the first bunch of days to be short distances km's wise, so at least you can take it easy ish and get ye ol bode back into the groove.

if it were me, that would be a priority, to be conservative for the first 2 or 3 days (or more) and not have to push too much.

It probably takes about as much time to lose fitness as it does to gain fitness.

I've heard six weeks is the minimum time needed to really notice a difference, certainly in muscle mass.

You don't HAVE to train. Due to a hectic life schedule, I frequently go months without ANY riding then will "train" for 100-200 miles total before heading out on a month+ long tour. I do short days (20-35 miles) at first then add in 5 mile increments if possible. I'm mid-50s so yes it is a little tiring the first week but after day7-10, I am in good enough shape to ride in the Rockies. I also have very low gears to be gentle on the knees. Of course, I am not a speed demon at first but I get back to a 12mph average by week 2.

Yes, it is much better to train before the ride as much as possible but you don't have to. You just have to choose whether you would rather tour even though out of shape or not tour at all. For me it is the former.

Being completely inactive for ten days might set you back, but if you stay active by walking, running or taking a few long hikes, there shouldn't be any problem. In fact it might help to be off the bike for a while. Besides if you are touring you can always stop whenever you want, and rest up before continuing.

I've never trained esp much for a tour due to time constraints but OTOH never laid off for a month. Only time the lack of training really hurt was on a loaded mountain tour. Maybe you could find a gym to work out in; run up bleachers or hills, do a lot of knee bends etc?

The knee bends thing is a good one. I realize this is because of my knee issues, but it's very much my knees that need regular moving and the muscles worked regularly.
The rest (cardio, other leg muscles) catch up fairly well, but my wonky knee gets weak quickly, or hurts when not used enough and then I overdo it a bit too much.

Training? Hmmm. I just ride my bike? Mt bike, errands, weekend loops etc. 2-3 rides a week is good. 1-4 hours on each.

Yep, same here. Stretched my commute this morning for 22. Wasn't able to get on the bike yesterday, but did 5 miles walking the dog. Going home this afternoon will be another 10 on the bike, and I may be able to ride to work and home for a meeting tonight, for another 12, plus another total of 4 or 5 miles walking the beast. We are supposed to get a few feet of snow midweek, so no longer ride on Friday (my day off) or Saturday, so I'll have to get the dog out for longer walks. This is how I'm prepping for a 4K mile tour starting June 9. You get a workout when and where you can.

You don't need to train. Just wear this shirt...

https://www.cafepress.com/mf/1879176...ctId=110717317

20 years?

well you better get cracking there young man, no dillydallying!

Raybo says he's been training hard which I think is very good considering the hilly tour route. My local fun rides are OK to prepare for easier tours but don't give the extra fitness to make mountain climbing comfortable. It takes a lot of concentration to train hard on flattish areas but the more fitness before the layoff, the better one will be afterward.

and from my experience, along with the shorter days for a bunch of days, having gearing low enough to make it easier on your knees is important--again, this is my knees talking, but I figure its got to be a good approach for anyone, just to be easier on all your joints and muscles.
I make a concentrated effort to downshift more often than usual, and all parts appreciate it as they slowly get stronger.

Find a gym near the places you'll be staying with a daily or weekly rate. Go hop on an exercise bike for at least an hour, a few times each week. I bet that'll keep you up to speed well enough that you won't notice much difference. Personally, I've never bothered riding enough leading up to a tour to be considered "training" anyway. My legs will get pretty beat the first 3-5 days, but after that it's all good. I actually went on one tour in February after probably not riding at all for a couple months(WI winter and moving to a new apartment). I was a little worried that time, but after the first three days, no big deal. Try to get on an exercise bike if you can, but if you can't, I say don't stress too much about it.

I have two thoughts: Years ago when I was working closely with a professional trainer for endurance MT bike racing, he had me take a full week off my bike before my "A" race which happened to be in the fall (The Vermont50). It seemed counter intuitive, but the results were solid. The theory being that the body benefits from a full recovery after a season of intense training.

Now skip ahead ten years and arrive at my second thought which is that I started a 1,000 mile tour last fall after putting less than 200 miles on my bike the entire 12 months prior. I was fine. My bike's geared low, I know my body, I was alone and I wasn't in a hurry.

You'll probably find yourself to be very strong and you might even be surprised at your comfort level after the rest. And if not, it shouldn't take too long to get back up to strength on the bike.