Paddle whatever is comfortable. You won't have any trouble keeping up with the rafts in a well outfitted play boat. Also, you don't need to have a long boat to play on the waves in there.
Basically, any kind of boat you take will work, just take one that is comfortable. So long as you have a solid roll you don't need to worry about having an 'easy to roll boat.' Honestly, its the roll, not the boat that determines if you will come up or not. If you are concerned about rolling in the big water, practice your roll a bunch instead of worrying about a boat.