I had 15 good years with my j-pouch (the first year of recovery was a little rocky of course). I could eat what I wanted, except for very high fibre items, but I did have to avoid alcohol because it made me extremely dehydrated. I had mild pouchitis a couple of times a year – maybe a day off work. I also had to take Metamucil before every meal, but I worked out a system and carried supplies with me.
Providing I stuck to my diet and medication regime, I felt fine. I worked full time, did yoga, ate lots of curry with friends, travelled to Japan, finished a certificate course.
The only thing I couldn't do was "be far from a toilet", so no camping or hiking. However, more intrepid outdoors types manage pretty well, from what I hear. And I rarely camped or hiked before the op anyway, so didn't feel I was missing out too much.
(This isn't a "happily ever after" story – after those 15 good years I'm afraid my pouch stopped working properly.)