I signed up for TOSRV and plan on riding the first day only. That's 100 miles.

Now I've signed up for Tour De Cure and 100 miles. On the NEXT Saturday! I just put two and two together.

I've got a training plan for TOSRV. Is a week later too soon?

I'm a clyde, but more of muscled beerbelly type, about 260 right now. I can do 25 miles with ease and want more. But I suddenly realized what I signed up for and wonder if I bit of more than I can chew.

You can do it. Just pace yourself.
I did 3 @ 100 mile back to back rides Twice last year.

It's not too much IF you ride more to get ready.

I would ride 35 miles every other day and increase your mileage until you are riding 50 miles, three times a week.

I would also do two centuries 2 and 3 weeks before the TOSRV.

If you can ride a century comfortably, then there's no reason that you can't ride another one a week later.

My schedule for the coming weeks looks like this:
Feb 20th - 200k Permanent
Feb 28th - 100k Populaire
Mar 13th - 200k brevet
Mar 20th - 200k brevet
Mar 27th - 300k brevet
Apr 3rd - 300k brevet
Then in May I'm doing a 400k brevet on the 15th/16th, (250 miles) and riding the Tour de Cure century course twice on the following weekend as part of my fundraising challenge.

Pace yourself, eat properly, hydrate well, keep your electrolyte intake steady, and never push yourself beyond your recovery limit. Try a couple of longer rides (60 - 70 miles) before your back to back weekends. Make sure that you ride steady and follow good nutrition/hydration, and see how you feel riding a longer ride (say 30 miles) just a couple days later. Get used to doing easy "recovery rides" to keep things limber, and get yourself used to pedalling through some initial discomfort in the first few miles after a long day in the saddle.
Just make sure that you slowly build yourself up to that first hundred. One of the mistakes I see so often is people trying to push too hard too quickly with increasing their distance, and they end up souring themselves to long distance riding.

25 miles (posted in OP)?? Is that the maxe ride you've done so far? IF so, you better get to moving!

Like posted earlier, if you've done a century with ease, back to back weekends is not too much of an effort...Heck, some riders do them back to back without stopping (double centuries)

Long distance tourists sometimes ride 100 mile days back to back while carrying their gear. If you ride enough beforehand, you should be able to do it.

YUp - No worries- a week later you will be well recovered. Hell a few days later youwill be ready to go...So I guess if you can do one you can do one the next weekend. Go ride..get ready and do a bunch of rides leading up to it. So a 50 miler...a 65 mielr and stuff liek that so you do an 80 miler than surely you will do the 100

Its not a problem if you are in shape for it.

during may - august last summer i was doing 250-350 miles everyweek (got layed off badass severance so , im fortunate , got my job back ) you can do it ! just listen to your body

It's not two much. But iIf the most you have ever ridden is 25 miles, it is TOO much.

Last year I rode my first century, and my previous max was 45 miles (four years prior). I did a 32 mile ride earlier last year, and I mostly rode due to peer pressure. I primarily ride for transportation (lots of 10 to 20 mile days, and lots of stops), and I'm 6'5" 225 lbs. I did finish, but if I could recommend anything: make sure you read up on nutrition. I had some water, GU gels, jelly beans, and hammer packet, but I think you need some more Gatorade/electrolyte type drink, or more salts. My legs cramped really badly around mile 65, and I had to stop every 10 miles thereafter. If you can avoid making this dumb newbie mistake, and have a bike that fits, I think you will have a great ride! Good luck!

Every time your power decreases by approx 7% you can ride twice as long (assuming you're seat is able to take it) so if you go slower than you think you should be riding you can go a lot farther.

I would suggest checking out https://www.outdoor-pursuits.org/ and finding one of the organized rides to do before TOSRV. Do the century or even the 60 mile Top of Ohio or Mid Ohio Century and see how you feel after a couple of days.

Actually, it's not a week it's a month. I'm mathematically depraved.

I'm preparing.

A couple years back I regularly rode unsupported weekly 80-100 mile trips into the Adirondacks. This was after two years of solid daily commuting with weekly totals of 200-300 miles.

There is no easy answer to your question, it's more an issue of saddle time, what kind of shape you're in, how quickly you can recover.