Two possible issues:
A. If you have a built-in generator in the RV, it will no doubt have a transfer switch with shore power. If you unplug from shore power and plug the cable into your inverter instead, and now also run the gen, can you get 240v? I don't know, but I do know it would be bad!
(With a portable gen, this is not a problem--unplug from inverter and plug into gen)
B. Many (some for sure like 7300s) have the converter on the same AC breaker as the receptacles. This means you can't use the breaker as the on/off switch for the converter, or your receptacles will all be dead too, defeating the whole idea. Now it depends on a bunch of things to do with your rig.
1.You can just unplug the converter from its receptacle if it is a plug in type, or
2. If it is "hard wired" you can snip the black wire into the breaker that comes from the converter, and insert a switch ( I used a regular household light switch) so now the converter can be switched off but the receptacles stay live with that breaker still "on", or
3. You can move that converter's black wire from the receptacles' breaker over to a different breaker you were not going to use off-grid anyway, like for the water heater, or
4. If the panel has room, you can add a breaker and make that one just for the converter, and use it as the converter's on/off switch.
