After reading everything again and thinking about it for a while (What a wealth of knowledge, btw. Thank you to everyone for all the great input!), I've come up with what I think will be a workable plan for my dry camping trips.
First, conserve! Led lights are a no brainer, so I'll definitely do that. More importantly, I'll really limit the use of the furnace.
Second, solar. Prices have really come down since I looked last, so to me it makes sense to go with at least a 100W setup. If I'm in a really shady site or it's cloudy, I may not get too much, but I think in most cases I should see a minimum of 10Ah per day. If I only need 20 per day, that's half my use right there.
Finally, I'm still going to try charging a second battery in the truck while driving around. I already have a second battery, so I may as well use it. It won't fit on the pup, so it will be riding in the truck anyway. All I need to do is make a pigtail so I can connect the 7-pin to the battery. I will leave home with it fully charged, then if I can pump maybe 5 Ah's into it each day, I should be in pretty good shape.
Doing the math, if between solar and truck charging I can average a minimum of 10 Ah's per day and I consume 20, I'm only down 10 per day. With two batteries, I'm leaving home with about 70 usable Ah's, so this should be no problem. Said another way, if I head out on a six day trip, I need 120. I'm bringing 70 with me so I only need to generate 50 while I'm gone. That's less than 10/day that I need to generate between solar and the truck.
The main thing for me is to keep this as simple, easy and fast as possible. As BFL13 said, this is camping, I want to enjoy the experience and not be worried about batteries and Ah's! I've been known to create some real Rube Goldberg contraptions in the past. I could tell you about the camp shower I came up with that is currently on version 12, or is it 13? (And I have some ideas for further refinements in the future!) I will say though, even though there is some effort to set up and take down, it sure is nice to be able to take a hot shower every night before bed. Plus my wife simply wouldn't be willing to go for more than 2 days sans shower, so this one really is worth all the extra effort!
Thanks again for all the great advice! I'm sure I'll still try a few different ways of utilizing the two batteries to find the best mix of max efficiency and minimum effort/fuss. I will definitely report back with the results after my next trip.
