Thinking of getting a golf cart as an airplane tug. Needs to be able accept a trailer hitch and go maybe 5mph tops. There are some on craigslist, but I thought I'd be better off asking here in case someone had a lead that was less sketchy than buying used off of CL.

Try the app nextdoor. Looks like a neighborhood Facebook but local to you. I see them sometimes up here where I'm at. Also if you have any golf communities local to you go check out in the clubhouse or the admin offices some allow residents to post ads on a bulletin board for things like that. My local cart store has all the trade in models in the back as well that they do something with I'd bet you can find something local to you like that, just stop by and ask. Where u located?

They are usually easy to find when they need batteries. Trojan is the battery you seek