Nice! The heated matresses are great - we love them, even though at first they felt like they weren't doing anything. They do work. They are only around 100 watts, so any generator should cover that.
Never checked the draw, but they are 12V, not 110V, so I think the amp draw is going to be high enough that they would kill the batteries pretty quick. 100 watts at 12V is over 8 amps, if I did that correctly. If you have a genny though, should be no problem.
2005 F-150 FX4
2013 Rockwood Roo 23 IKSS