Folding is way too nitty for my taste, but obviously it's not a huge mistake, since it doesn't cost you anything, and your hand is marginal. I'd never limp here; you're just asking to flop 357 and go broke to someone who saw the flop with 46s, for one thing, and you'll have trouble representing a hand on a high board for another. So I'd be standard-raising here at any table where I didn't think I'd get 3-bet really really often. If I thought I'd get 3-bet a huge percentage of the time, I'd open-fold, since I don't need to get into coinflip spots at crazy aggro tables; it's easy to find much better edges against those types of players.
So, it's a bit hard to make the best decision here without knowing something about your table. Maybe you shouldn't be playing 12 tables at once?