Solar is set it up and forget about it completely. A 100 Watt panel will easily keep a 110 AH battery at 100% of charge and it will do it when the camper is not in use.
I passed on a generator that would require taking up valuable storage space and needing to carry a gasoline canister and having to babysit it while it was charging the batteries. I don't want to have to run the generator for a couple hours or longer in the morning to recharge the batteries. With solar the charging is taken care of whether we are at the camper or off hiking or fishing or whatever.
Generators are fine for people who cannot take the heat or can't cook without a microwave. For keeping batteries recharged it is the worst solution I can think of by a long shot. With two batteries pre-solar we could go 3-4 days and have them at 50% or more DOD and then recharge while driving and using the truck's generator or pulling into a campground with hookups for a night.
Adding a second battery if your RV only has one is the first step and the least expensive to do as it makes use of your existing charging systems. The Trimetric is the second step so you can accurately monitor their charge state.