Strange Electrical Issues

Batteries are wired correctly. I have one cable going from pos-to-neg between the two batteries, then the trailer leads go to their respective posts (in my case, backwards from usual). I did some more digging. When I tested the leads, I was trying them the way they're supposed to be wired, but mine are backwards. Apparently, if you use the multimeter backwards, it'll go backwards. Go figure. So I've gone back out and tested the leads again, but in 'reverse'. I'm only getting about 11.5 volts from them, so I think there's still an issue. But at least I don't think there's a major one any more. If we do what we normally do, and run both the shore power cable and the 12v charger from the generator, that should be ok, right? Please tell me if you disagree. Then we'll get it checked out by someone when we get back from our trip.