Agreed. If I was usually camping with hookups and only rarely boon docked, that is a good option. You already have everything you need to do that so it saves buying and dragging around a genny or solar modules that you use only a few times.

If you're often camping without hookups then its not a great way to go as it uses a lot more fuel and charges slower that a generator would. Solar is the best if it can meet your power needs as its clean and silent, less expensive than a genny, and uses no fuel. 

That is probably the best way to charge the battery fast since the converter will be able to bulk charge the battery/batteries faster than connecting the umbilical to the tow vehicle would. You could use jumper cables from the tow vehicle, but if you have a generator, that is probably better. The down side to a generator is the need to carry it somewhere plus the fuel and oil to run it. Keeping it maintained is important also. The noise is also a big consideration. When you are in a quiet campground and someone fires up a generator, the sound really carries. It is not a way to win friends unless you are providing power for them also. Even inverter generators are only relatively quiet when compared with a non-inverter generator. Any of them would be noticeable in a quiet campground. Plus there may be limited hours when running a generator is permitted, if at all. Check the rules.

If you can get solar, that is good. However, that is depending on if you are in a place where the sun will shine on them. If you are in a wooded area, that is not as feasible. Nor is it if you are likely to have significant cloud cover. You know your situation best.