Toyhauler battery configurations (bumper pull)

I’m looking for options for configuring the batteries on my bumper-pull trailer. I have four 6v batteries. In the past I've had two on the tongue and two that I keep in a tote and schlepp out with me and connect to the house batteries once we get to camp.

I’m at an interesting crossroads because:

1. The two batteries on my tongue (and the nice marine case) were stolen, so my trailer tongue is a blank canvas, so to speak.

2. I burned the hell out of my finger on our last trip out when my wedding ring touched the diamond plate on the front of the trailer and completed the circuit between the trailer and the wrench I was turning.

So my tasks now are to find a new good box to house the two batteries on the tongue between the front wall of the trailer and the LP tanks and to devise a cleaner connection so my wiring isn’t such a rat’s nest.

I thought I’d throw that out to the brain trust here:

1. What boxes can you all recommend for two tall batteries end to end on the tongue?

2. What kind of junction terminals can you recommend? I would like to end up with the two batteries connected to each other in series, all the coach wiring going into a junction, the two batteries on the tongue connected to their own terminals on the block, and the other two batteries in the stand-alone tote similarly connecting to their own terminals on the block. Ideally connecting and disconnecting the extra set of batteries wouldn't ever interfere with the coach wiring connections or the other battery connections and nothing would come loose when I hook/unhook the second set.

Suggestions?

Oh and the two lessons I learned: (1) Gold is very conductive and (2) I smell delicious when I’m searing at high temps.