OK. Ditch the suicide cord idea.
(somehow knew that wouldn't get a positive reception)
Instead switch the EMS to 15s and run the trailer power cord to inside the pass-thru .... I should be able to mount a socket for the trailer power cord just under the pass-thru floor on the side of the trailer. Then a short bit through the floor to the inverter.
That gets me power to the kitchen sockets which would be nice. Will somehow run the on/off remote wire to a convenient location nearby.
Have a spare slot at the batteries for another fuse. I don't want it blowing all the time (they're expensive).
Inverter's surge rating current: ~2000W/12V=167A
Inverter's 5min rating current: ~1100W/12V=92A
So 100A Blue Sea MRBF fuse ???
Looks like it has about 2-10s before blowing at twice its rating. And 1-2 min at 150% of its rating.
https://www.bluesea.com/products/5183/MRBF_Terminal_Fuse_-_100ACable size? About 8-10' total (+-). Have some #6, but that would give 3.3% (0.4V) drop at 100A (12V). Might just use that for now as hopefully our loads will be a lot lower than 100A. This whole thing started with a COFFEE GRINDER for goodness sake!!!
And just realized that if you have AGM batteries inside, not on the tongue, you can mount the inverter *right* next to them. Maybe one of these days ...