I've been struggling to get a bike that fits, ... still working on it (need to install long stem & new brake/shifter cables due to new handlebar height.), but just the same I've been riding these small 3-mile rides with my kids about once a week. Well the first ride I was nearly dying after a mile, as the first 1/2 mile is all uphill, although it's a gentle slope. I've probably only ridden this 3 mile stretch (1.5 miles out and back) once a week for the past month or so but now my kids and I can ride it without stopping and it's getting easier. The past few times have been painful in the knees, so I haven't pushed it, until yesterday, then I pushed it and my youngest almost kept up with me. I'm 40, 285-lbs @ 6'4"... shamefull, they should be riding circles around me at 11 & 12-yrs old. We'll now be riding this little ride every day it doesn't rain and hopefully graduating to longer rides down to the lake this weekend. Oh yeah, and my butt is starting to toughen up so that I prefer the smaller harder saddle over the cheap-o vinyl brooks w/springs. Still looking forward to being on a bike that fits... I can see that being a whole different experience. 2 weeks ago I scored a Motobecane Nomade and even though the bike needs a bit of work(new front wheel/taller handlebars. raise seat to match etc.) I really like the ride over my slightly smaller Puch.
So what's interesting is that just this little bit of excercise and trying to eleminate fast food have lead to my bringing in the belt a notch and every now and again for no reason at all I get this really weird feeling of feeling good... like a sense of wellbeing and strength.