That's what I'm best at, overthinking!
So if I understand you correctly, the simplest course of action for me when 'in the driveway' is to keep everything on (except solar). Samlex drawing on batteries to power RV parasitic loads (including fridge control board while operating at 120V). When the battery voltage hits 12.2V, the charger kicks in on low threshold and charges back up to 100%, then rinse & repeat... ?
When cold weather kicks in, everything will be disconnected anyways.
PT, I didn't have any intention of changing the battery bank voltage, not sure how that came up?