Welcome to the forum
Without knowing your set up I am going by assumption based on your statement "2 sets of wires" and Two batteries.
If you have 2 12V batteries, then the proper way to wire them up is to join the batteries in parallel, meaning both positives are attached and both negatives are attached to each other (+ to +) and (- to -). Then the leads to the trailer should be attached with the positive lead on one battery and the negative lead on the other battery. Some dealers will put the trailer leads on one battery and then just jumper the batteries together.
Are your lights LED or incandescent? Water heater will use some battery for DSI ignition, fridge will use some battery for control board and DSI ignition, water pump will use battery when running and if you have an illuminated switch, it will use battery when turned on.
Without knowing what size batteries you have, And how they are connected, I would say with incandescent lighting, water pump and appliances, you did good if you got 36 hrs.
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2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.
Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.