Edit: Double post, don't know how to delete.
Thanks for all the input everyone. I do use W/Hr for my calculations, I have a small amount of electrical training. Thanks for looking out though!
I do not plan on using regen breaking, as any benefit would likely be lost by the time I factor extra tire wear and complexity.
I plan on having 2.8 to 3.2kw of solar, (Haven't settled on panels and setup), that will be the main charge and by my calculations should be enough to run everything in the bus while still putting a charge to the batteries in the day. Assuming I'm not cooking, doing laundry and taking hot showers all day, every day, it should work.
The hope is to not need a genset at all. I have a gas one I'll probably take for the first year "just in case" but the large battery and solar is to hopefully get away from needing it. I can't justify thousands for a diesel gen when I'm already putting that towards solar.
Assuming the Leaf idea can work, I can actually take it to a charge station and top off and reconnect instead of running a generator as well.
As for how I'm thinking it will work at the moment: Solar--->transformer--->bus auxiliary battery bank and systems<--->Nissan transformer/charger for leaf(bi-directional)<--->Nissan Battery
I'm hoping that with this setup I can actually pull power from both battery banks if needed and increase the available amperage without the need for a larger transformer in the bus. (Though I will technically have two small ones anyways.)
For those wondering, the Leaf's full charge its battery pack is around 400v stock. The bus bank will be a much lower voltage 12 to 48, depending on the solar system/transformer and appliances we decide on. If I do this idea at all, I will just be using the Nissan charger after the ac conversion from the bus solar for safety and insurance concerns.