Unless you want to run your a/c while boondocking and can't or  don't want to run a genny continously.  The a/c load is about 10x everything else put together,  which leads directly to a much larger battery capacity. You can't get enough solar on an RV to run an a/c for longer than maybe 6 to 8 hours, but you can limit generator operation to a few hours a day if your battery bank and generator are large enough. That is what I'm working on doing currently. 

 The power levels become high enough that 12V is a liability due to high currents/resistive losses. So I am planning to go to 48V, which is the standard for both off grid homes and small EVs like golf carts, so there is lots of equipment available at that voltage. 48V reduces currents by 4x and resistive losses by 16x, improving efficiency and greatly cutting copper cost and weight. 

 There are nice all in one integratex inverter/charger/transfer switch/MPPT controller units now available that are very inexpensive and eliminate a ton of wiring and components. I'm planning to use one of those (3kw), my existing 4kw generator, 280ah (14kwh) Li batteries, and about 800w of solar. I'll use a small 48 to 12 dcdc buck converter for my existing  12v loads. I probably wont install a 12V to 48V boost converter for alternator charging as I doubt I'll be on the road enough to make the small charge current I can get from the alt worthwhile. I can always all one later. 

Overall by using an all in one inverter and building a diy Li battery pack I'm hoping to bring the total conversion cost in under $5k. Most of the $ goes into the batteries of course, but that is what provides the flexibility to postpone generator operation till it's not objectionable.