Some links that do a better job of explaining RV Electric than we do:
MyRV Electric does an excellent job of explaining how these systems work.
RV Electric Power For Dry Camping goes into great detail, and 'Dry Camping' is similar to boondocking or Overnight RV Parking.
Technomadia builds a lithium battery bank.
Technomadia; Lead Acid battery downsides.
Technomadia; Lithium Ion Advantages.
Mastervolt MLI 12/320 Lithium Ion Battery
Current Price (as of blog publish date) on MLI 12/320: $6,635