We obviously aren't as fit as you!! We didn't ride the whole thing--couldn't have. In addition to riding the tandem we also hiked, kayaked and mountain biked so we didn't put a huge amount of road miles in. We drove there (from Minnesota) so we had a car the whole time and stayed several places from Banff to Jasper, using where ever we stayed as a base camp and doing day trips from there. We stayed at Lake Louise a couple of nights (the town, not the big château) and hiked and mountain biked there and biked the old highway (1? 93a? I forget) to Banff and back on a day trip. Then we stayed at Emerald Lake, but only hiked and Kayaked there. We were going to stay at The Crossing for a couple of nights and use it as a base to go South one day and North the next, but disliked the place so much we went straight to Jasper and extended our stay there. We stayed 4 nights just South of Jasper, and biked to Maligne Lake from there one day and to Athabaska falls another and Mountain biked another. We also had some down time.
The weather was all over the place. (7/2-7/11) We were prepared for pretty much everything so it wasn't a problem. Most days started out nice and then clouded up. It rained at some point in the day more often than not, but we never had a day that was more than about 25% rain. Temperatures tended to reach around 70 most days with a couple days being sunny and approaching 80. On the way back from Maligne Lake to Jasper (about 35 miles, almost all down hill) we were either in bright sunlight or rain, sometimes fairly heavy. You could see it coming (and going). We hit our current record of 54mph (on those damn Paselas, no less) trying to stay with a patch of sunlight and ahead of some rain.
All in all, it was a wonderful trip. So much so that we were kind of crabby when we had to leave. I'm not sure when, as it will take some time to pay off the credit card, but we are absolutely going back. It was a truly amazing place.
To everyone else, this is a fabulous place to ride. If you are considering it, I recommend it without reservation. I found the mountains to be more enjoyable than the Rockies in CO, WY & MT because they weren't so arid. The scenery just never stops. And the roads were great. There was plenty of room to bike and as the whole thing is a parkway, speed limits are low and cars tended to be more polite than on normal highways.
And to top it off, we got engaged there (!), so we *have* to go back and celebrate once in a while.