[Pokey]

The unfortunate part is that you're first to act. There wasn't anything more you could have done to clean up your outs: going for a check-raise anywhere would likely have gotten the hand checked through.

Given how incredibly bad your opponents are, I think you have to bet this river. You're really only behind a stubborn ace, and many of those will just call the river out of fear of an 8 or a bigger A. Also, smaller pockets, loose 5s, and loose 4s are likely to call you if they really are as bad as you say they are. Your river bet is probably +EV, but not by much. Note that you're never folding a better hand with a river bet, so the only question is whether worse hands will call or better hands will raise. I think the answers to those questions are "often" and "rarely," given your description.