You said in post #3 the GFI was popped and could not be reset. That could be the main problem because the other outlets are tied to the GFI.
Next you said all the AC worked when you ran the Generator. So I assume you were able to reset the GFI when you ran the generator. Once the GFI was reset everything worked -- so sounds like their is nothing wrong with the RV GFI.
So when you plugged back in to the garage it sounds like the GFI in the RV popped again. Like Jegdrum said it is not uncommon for a GFI at home to be incompatible with the GFI in the RV. Are all your garage plugs connected to the garage GFI? Can you find a Non-GFI at home and try plugging in to that?
Also before you plug in at home be sure everything AC in the RV is off (A/C, Water Heater, Refrig, and nothing turned on that is plugged in to any wall outlet). Plug in at home and then try turning on thing plugged in to a wall socket. This precludes any AC power surge at plug-in due to load.
Also, what is the rating of the extension cord you are using in the garage. It should be at least middle weight, or heavy weight preferred.
Ed & Bev Felker
Retired USAF Col and retired Nurse
Traveling with Lily & Bella ('Teddy Bear' breed)
2015 Vegas 24.1 (E-350)