With the 15 Amp connection, you need to run everything you can on propane, Hot water heater, stove, refrigerator, furnace. Use 12 volt lamps instead of 120 volt lamps because the 15 amp won't run much besides a TV and coffee maker at the same time. Your microwave is questionable, depending on it's size and how much current you actually have at your hook up. Some of the 15 Amps, if they are heavily used, aren't 15 Amps. I've seen them as low as 11 or 12.
I have done it for several weeks on 15 but had to do a lot of turning on and off to balance the load.
John