All is well now. Batteries are holding a charge and charging like they should. I was not using the camper. I did turn on the light in the dump valve bay looking to see where I could possibly route some wires. The only thing we used might have been using was the interior lights. Slide had not been moved for a couple of months.
I don't have a clue what would cause that 30 amp fuse to blow. Other than storms, but given it was a 12v fuse that blew, I'm not sure if a surge on the ac side would make a 12v fuse blow. But then again, I am no electrical expert.