We don't use any of the electric heaters that have open flame, red hot cores, etc as they would have to be turned off when we were not around. You have no idea what roams the floors and walls in your trailer at least we don't haha.. You also don't have worry about a curtain catching on fire as well...
I would seriously think about the oil-filled no open flame type heaters. They will warm up as good as any of them. BTU's is BTU's
Just my thoughts on heaters...
Oh we also use the 20AMP Service at the camp ground pedestals all the time. They are on separate breakers so its free to use and won't take away from your 30AMP side. WIN WIN WIN for us. As a matter of fact this is the power that runs my oil-filled heaters when we use them.
Look around you should be able to find a way into your trailer. Perhaps the seal around the storage bay door will let you run a an extension cord thru and still close the door. Some folks add a MALE weather tight 120VAC 20AMP receptacle on the side of the trailer behind a lid door. Then they have a special 120VAC extension cord that fits their MALE receptacle...
Definitely a way to gain some more power in your trailer for sure...
Roy Ken
My Posts are IMHO based on my experiences - Words in CAPS does not mean I am shouting
Roy - Carolyn
RETIRED DOAF/DON/DOD/CONTR RADIO TECH (42yrs)
K9PHT (Since 1957) 146.52M
2010 F150, 5.4,3:73 Gears,SCab
2008 Starcraft 14RT EU2000i GEN
2005 Flagstaff 8528RESS