If your looking for something that literally ANYBODY can get on and ride I suggest a polaris trailboss 330. Full size chassis, very forgiving, automatic trans with reverse, will do 40mph in sand bone stock. I have 2 of them and have beat them from michigan to oliver springs tennessee (coal creek ohv area). Awsome for trails.
I bought a pair for me and wife back on '04 and we had a lot of fun with them and they are still ready to run today. You can find them on craigslist only a couple years old for under $2000 all the time.