So I got the BlueSea
6 circuit fuse block today (w/ground option and rated at 100 amps). I mounted it 23" off the deck..
I decided to be smart.. The bottom left is the FEED + from the battery box and trailer tongue with a 20 amp fuse for inbound 'juice'..
The right side is the 5 amp for the factory Bargman cargo trailer light and the 10 amp is for the Sureflo water pump with 7.5 amp max draw (that recommends a 10 amp..) I left slack in the wires.. cause you never know..

The wires coming down from the 'block' are for the water pump.. the blue 'shallow old work' box (at 48" off the deck) is for the wall switch for the water pump.. No worries the wires are zip tied and apart up top..

The shallow old style work box is Carlon B108R and is flanged and only 1" deep.. which works well for trailers with 1" thick wall beams.. and another 3/8" of more of depth.. For $1.49 from local TrueValue.. or $1.29 from HDepot..
@McDave.. got the IM's.. still pondering which way to go.. Will let you know in a few months..