awesomeame, although i havent had ostomy surgery (yet...) i have had 2 abdominal surgeries related to crohn's disease. it took me a good 3-4 months before i could go to the gym and even do the lightest of weights. with time though you'll be fine. you will lose strength and muscle mass from not going for such an extended period of time. in my case, i lost 20-30 pounds, but then i had a horrible experience and was on liquids or nothing for about 2 weeks which caused the extreme wait loss. anyhoo, my surgeon blew a fuse when after a month into recovery from my first surgery i wanted to gauge me strength and tried to a push up, which i couldnt do. he really admonished me for doing that. so although i havent had an ostomy yet (i am praying i wont have to, but like you i have asked some questions to find out what to expect so i visit here once in a while) i have had similar experience in recovering from abdominal surgery.
Crohn's since 1993 (age 17)
been on every med available, currently on entocort, colozal, 6-mp, remicade
surgery in July '05 - removal of 2 inches at ileum and 8 inches of sigmoid colon (had fistula into bladder)
Nov '05 developed colonic inertia; has improved somewhat w/ adoption of organic diet (maker's diet)
now contemplating ostomy surgery due to severe perianal disease and colonic inertia