We use a set of # 2 guage 12 foot jumpers to hook up the 2 AGM batts in our pickup to the 2 travel trailer batteries .
We park the trailer and just turn the pickup around .
The pickup gets driven every 2nd or 3rd day .
We hook up all 4 batteries as soon as we return .
The 4 batts equalize .
We dry camp .
We do a 9 day boondock every summer since 1984 .
Our setup has worked well for over a decade .
This works good . no genny . no solar .
For heavy current draw I consider Roy B to be the expert .
For heavy duty needs RoyB says two 6 volt GC2 golf cart batteries are the only answer .
I replaced my duramax pickup batts with Exide Edge AGM group 78 for $ 140 each from BiMart .
Like my Pop said " There is no substitute for cubic inches " .
That includes batteries .
Do a Wikipedia about AGM batteries and you will find the reason we made that switch .
Over time we have converted to AGM in our cars,truck, boat, and TT .
I stopped running my pickup to recharge the RV batts many years ago .
The switch to 4 big AGM batts works for us .
But the real game changer is to use the heavy duty jumper cables and run off of the 4 batteries .