OP I am a lot like you. I have changed to LED, I only turn on the water heater want hot water, my CO / smoke detector is one of those lifetime lithium battery powered ones, stereo when off has no memory back up, TV is LED etc. etc. My parasitic loads are pretty low. I have 2 6V GC2 batteries rated for 205AH, meaning you have about 100AH if you only take them to 50 percent. If your parasitic loads are about 1/3A, then they only use 8AH per day, or 24AH for a 3day weekend. In my case, I can go 3-4 days being conservative. I also sometimes go below 50 percent if necessary. Doing so can reduce the total number of cycle life of the batteries, but I camp a few times a year so it is not as much a factor as someone who cycles the batteries daily.