OK, firstly, be aware that there are two separate "things" people confuse often because they are spelled similarly: "inverter" and "converter." And it is critical you know the difference.
Every rig has a "converter." It's function is to take 120 volt shore power and make 12 volt DC power for the lights, recharge the battery, etc. It also distributes 120 volt power to the AC, microwave, and 120 v outlets inside and outside the rig.
An "inverter" takes 12 volt DC power from the battery and turns it into 120 volt AC power. There may or may not be one on your rig, in fact, probably there isn't one. But there could be.
This is important, because if you power the same outlet with both a converter and an inverter, the latter will explode in flames. Really. And if you ask for help on one but mean the other, the answers will be useless.
If your GFCI breaker pops every time you plug in, the most likely cause is that the outlet into which you are plugging your RV is wired improperly. The hot and neutral wires are switched. Amazingly, this happens a lot. For reasons nobody knows, the guys who wire houses are very lazy about making sure those connections are right. And the problem could be at the outlet, or it could be at the main breaker box in the house. If the box is backwards, and the outlets are right, every outlet will be backwards. Isn't that hilarious?
It is also possible that the GFCI in the RV is wired backwards.
The test is simple, but does require a VOM, a volt-ohm meter. While there are fancy/expensive ones, there are also cheap ones (like, $10) that will do what you need to do: find out which wire is hot, which neutral. There are also very simple "circuit testers" that you simply plug into the socket, and the display of lights on the tester will tell you whether it is wire right. You would be well served buying one and using it on your house, as well as on your rig, and absolutely on the hookups at campgrounds before you plug in. You'd be astonished how many of THOSE get wired backwards for exactly the same reason houses get wired backwards.
