I go to Chatfield all the time during the week. I am a subscriber to EJ's method. One of the things he said in that DVD is he does like 50 rolls when he gets out on the river.
I don't know about getting 50 rolls in a day while I'm riverrunning (seems like such a hassle. I get a handful of purposeful rolls when I riverrun, at most. Even if it's all day.) but I do get out to the lake frequently and get in tons of rolls, there.
I remember when I was first starting to roll (about 1 year ago
ah, to be young again), and I felt like I only had a few combat rolls available to me for the whole day. If I had to do more than 2-3 rolls, I was afraid I would swim. I think veterans tend to forget about roll-practice, but it's a huge muscle-conditioning thing. It's easy to forget just how much work goes into a solid hip-snap.
So anyhow, I like to get several dozen rolls at the lake, at least once a week. I'll at least have a few rounds where I alternate rolling on each side, and keep count. I feel like I can roll all day, but when you actually start rolling until you can't anymore, you'll be surprised how few you might be able to do. (I got to like 70 and started to get really sloppy).
Anyway, just my .02. In no way do I mean to brag, or anything. It's just what has worked for me. I owe it all to EJ's Rolling and Bracing DVD (the "For Dummies/Complete Idiots Guide" of rolling, I think).
Let me know if you want to practice with me.