L;
I was delayed in completing my prior postand missed some intervening info. This would be so much easier sitting around a campfire!
What I posted goes a long way to eliminate the need for an aux/house battery. At the same time it lowers the need for a solar system due to the enhanced alternator. A house battery solves your 12V cable length issue but complicates the charging approach.
The lifeline is a top-shelf battery. IIRC, it really works best with a kick-azz charging system. I defer to MEX on condoning your charging approach.
The DEKA 31 would be a good economy dual-purpose solution.
HTH;
John