If you get a generator, remember the gas cans.
A friend loaned me a Honda 2000 generator for a few weeks over the summer. I was surprised by how little charging I got on a tank of gas/on a few hours of charging, when compared to the output of the solar panels. IIRC, I got 20 amps of charging for a couple hours run (not the full tank, by the way), run through a Xantrex 2000 inverter charger into 330 amp hours of gel cells. That's 40 amp hours a day. I'd get about the same amp hours with another 100 Watt solar panel, without the hassle and noise. (Even the Honda makes some noise at it's slow speed. I ran it in the evening, and sound carries over water, especially on still nights, so I didn't run it when the stern was facing the closest shore.)
Yes it helped, but really the benefit was when the kids wanted to watch TV or I was using the microwave. This was also the time of the evening when all the interior lights were on. (And I did turn the freezer to a colder temperature to take advantage of the extra amps.) It got so I'd start it until dinner was over and the movie was over.
Don't get me wrong, it was great to have, expecially as a battery-drain preventer. It simply got me wanting more solar instead of a generator. For the price of the generator, I could get more solar panel charging (including the cost of some mounting hardware), and never have to carry any gas. This might be different if you have AGM batteries that can take a quick charge really well, or if you are using a different charger (the Xantrex 2000 was only pushing 13.6 volts, while the engine's alternator pushes 14+ volts during charging). But if you were putting more amps in, the generator would probably not be running at the low rpm setting but at the higher, noisier rpm.
Regardless what you do, get a Victron battery monitor. Without it you don't really know what's going on with your electricity.
Regards,
Brad