I've done a few different things over the years to extend my boondocking stay time. I almost always boondock in the forest so solar is out for me. The first thing I did was to replace my pair of group 24 batteries with a pair of GC2 golf cart batteries. This gave me about 220AH capacity with much deeper non-destruct deep cycle capability than the marine/RV group 24's.
However, I didn't discard the group 24 batteries because they were still good, so I would charge them at home and haul them with me well strapped down in the back of my tow vehicle. Then I had another set of batteries I could swap in when the main batteries ran out.
Finally, now I bought a Champion 3100 generator so I can charge batteries and run AC if I want to. I only use it sparingly, but it definitely extends my camp time. I've given the group 24's to someone who needed them. I'll probably upgrade my charger so I don't have to run the generator very long to bring the batteries up. The generator weighs slightly less than the pair of group 24 batteries.