I just booked a camping bachelor party for my buddy last week. Ended up booking a group site by Rocky mountain House / Nordegg, it has a private locked gate and a couple outhouses. Also has a cool stream going right through it that is apparently good for fly fishing and has quad trails right out of the site. We just rented a big outfitters tent and will be playing drinking games all weekend with nobody to bother us. Not sure if that's quite what you're going for but maybe check for group sites around Abraham lake and rent a boat / trailer/ motorhome?
Good luck and have fun