1. As far as your basement is concerned, don't waste your money with an Edenpure. If you just must have that type of heater, then Ace Hardware, Home Depot and Lowes sell the same type cheaper.
2. You trailer does not have an inverter, it has a converter which changes 120 volts to 12 volts. An inverter changes 12 volts to 120 volts.
3. The only time your 120 volt outlets will work is when you are plugged into shore power or a generator.
4. Electric heaters work very well heating a trailer. They do draw a lot of amps, about 12.5 amps each, so with your 30 amp service, you are limited to 2 heaters and then turn one off when running the microwave, electric water heater, or hair dryer.
5. Distributing the heated air is as important as making heated air, so many people prefer the Vornado brand of heaters.
6. Heaters with digital thermostats will keep you more comfortable as they keep the temperature more uniform.
7. In very cold temperatures and depending on your trailer, using your propane furnace may be necessary to keep the holding tanks and water pipes from freezing.