Check out Jeep Outdoor Club of Central Iowa. Jeep Outdoor Club of Central Iowa - JOCCI
I'm a member, we have access to private wheeling area down by Oskaloosa and have club runs there and other places year-round, as well as monthly meetings, talk and tunes, BBQ and beer, etc... I'm in Cedar Rapids so I'm too far away to go to the meetings but I usually get in on a couple wheeling trips a year. Just got back from Moab with some of the guys from there about a month ago.
Also check out Iowa Jeep Club. They're open to all 4x4's, they're leaving for Ouray Colorado this weekend I think. Not sure if they have a website, but search that name on Facebook and they have a group. JOCCI does too, under the long name.
Pretty sure both clubs have members in Ames.