Having owned and own a couple of expedition vehicles, my recommendation for you is a 4x4 Frieghtliner or International Chassis with the box/RV built by Showhauler out of Indiana. Built like a tank, they should be able to meet your customization requirements. It will have the comfort your wife is...
I have a new Zero FX and will be using it with my EarthRoamer LTI. I will be playing with the charging and I will let you know how it goes over the next few weeks.
It is a CZONE controller. The EarthRoamer HD's have been using CZONE for a couple of years. According to the owners, this is a fantastic control system that is simple to use, reliable, and integrates all of the electronics.
I have had a ER in all of those locations for weeks on end. There have been multiple ER's up in the Yukon, Arctic Circle and Alaska this summer. Their will be ER's headed to Mexico/Baja and Central America this Fall and Winter. Great vehicles and wonderful service provided by ER.
I think you should look at a new Tiger or a used Earthroamer. Enough size to be comfortable and host guests, and capable of getting you to campsites that most others can't get too.
Having a similar background as you, as well as a large expedition vehicle. I always carry a good shovel, actual maxtrax type traction boards, and a tow rope in addition to the equipment that you are currently carrying. I have used my winch, as well as the items listed above on more than one...
I had Adventure Trailer build a motorcycle trailer for my motos. I have trailered two GSA’s for many consecutive days off road with out any problems or limitations.