Stand alone starting battery for generator

I have a 2013 FR 40' XLR 395AMP and plan to do the same for similar reasons. I plan to add an (1) extra battery for the house power and add another (1) extra battery for the Lippert Leveling system and Oman 5500 Gen. I want this battery separated from the house power for same reason. For a total of 2 12v batteries for house power and 1 isolated 12v battery for Gen and Lipper system.

At some point, I may plan to add solar panels to supplement onboard power to limit Oman use.

Any help with direction or electrical diagrams would be helpful.

thanks in advance.......