It is really about how long can you go with batts part down before desulfation back home is no longer possible, compared with how long your trip is away.
Probably? with vacation time length RVing, the big battery bank with "some solar" is fine to still be able to desulfate as needed back home. When retired with longer times away is when you need a new plan.
I still like the gradual approach using portables that you can nail down later if that then seems like a good idea and you will be keeping that rig