You need to keep your truck battery up, and I suspect that one hour of driving is barely enough for that. So there is nothing left for a coach battery - swapping or not, doesn't matter, you just don't generate much energy daily.
Try and add one more battery.
Also, you should consider a solar. A portable 100W panel can be placed far enough from your shady site to catch some light. Solar still works in the shade - if this is a diffused shade like from trees, but it will be much less than in direct sun.
With or without solar, you still need to conserve the energy, so here is what you can do:
Replace all the lights with LED.
Use a AA-battery radio or Ipod dock that has no bright display and no remote, rather than powerful 12V audio system of trailer.
Get a catalytic heater, preferably - Platinum Cat heater, it costs more than Olympian heater but it is better.
Get a comforter as thick as possible, with a fake down filling aka "down alternative", they probably don't make it with a real goose down these days (or charge a fortune). Can't recommend any in particular, there is plenty on Amazon. With down, the warmth is measured in "fill" - the more down is in there, the warmer it is. The higher the number, the better, fill 800 is better than fill 600. With synthetic fibers I don't know how they estimate the warmth, so just get the thickest and heaviest one, with "baffles" - those stitched squares, this is to prevent the fake down from shifting around.
