Most appliances really don't care if the power is 50Hz or 60Hz, even if they aren't rated for either frequency.
Timers may run a little slower. Some clocks may not keep accurate time (though I'd think most digital ones these days that use the power line for reference would be programed to self-adjust to 50 or 60 Hz). Pretty much everything else works just fine; motors don't care much if any, even synchronous motors, and heating elements certainly don't care, and phase control works all right for things that use that. Switching power supplies absolutely don't care, and indeed virtually all would officially be spec'd for both frequencies. One I just looked at (which is hardly atypical) is rated for operation from 100-240V 47-63Hz.
One device common in some RVs (but not the OPs) that would be of concern are older ferroresonant converters. Their output voltage is fairly constant over modest changes in input voltage--they have reasonably good source voltage regulation--but is rather dependent on the input AC frequency.