What he said.
Starting batteries for trucks are a little different than starting batteries for cars, in that car batteries are truly cranking batteries, and truck batteries are a hybrid. Internally, truck batteries and marine "deep cycle" batteries are identical. The only difference is the terminals. (You can really see that when comparing Optima batteries, comparing the yellow top Group 31 truck batteries and the blue top Group 31 marine batteries - identical everything, except for the terminals and the color of the case. It's all in the marketing). Marine and truck batteries are a hybrid between starting and true deep cycle batteries, in that they are made for cranking the motor and they are deep
er cycle than a regular car starting battery (but not deep cycle). They are designed for the low amp draw of a few lights and a trolling motor, or on a truck, the same type of draws - a few lights, fan, laptop computer. Low amps draws.
It's best to use the truck batteries for whatever the truck needs them for, and use a separate, isolated house bank for your crap. If you only need to run low amp draws like lights, computer, a TV, then a battery bank of truck or marine batteries 2, probably 3 or 4 12-volt) is fine. If you want to run a fridge and/or microwave, then you want true deep cycle batteries with thicker and taller lead plates like high dollar gel or AGMs, or semi-high dollar wet cells like Trojan golf cart (or the more robust floor scrubber batteries). Otherwise, be prepared to replace the entire set of truck batteries on an annual basis.