I would ask;
• How often was my current battery not enough for my needs?
• Am I planning on increasing my battery consumption enough to justify cost of an improved system?
• Do I really want to fuss with a generator or do I have enough stuff to maintain.
In my case, I have the standard issue battery that came with my TT. We rarely used it except for a couple of overnight camps with no hook-ups and once during a camp ground power failure. If careful we could squeak two or three days from it. We simply do not camp away from electrical power, enough to justify hauling anything bigger. Our camping without shore power usually involves a canoe and tents.
If you are planning or do a lot of off grid camping that is certainly another story.