Does it have an inverter already? If so, the battery connections are usually self explanatory, and the rest should already be connected properly. If not and you are going to buy an inverter, you have to consider the system requirements first, and then design and install your power system.
This is simple if you understand charging systems, automotive wiring (including wire sizing and voltage drop), amperage draw, inverters, chargers, fuses, and circuit breakers, as well as shore power systems. If you don't and you DIY, you could cause yourself a lot of grief. But if you just drive into an RV service center, you could end up paying way too much for a simple system.
Get together with a friend (or friend of a friend) who is good with automotive elec. systems, offer to pay a reasonable rate for time, try to get materials at cost, and go from there. Find out your truck alternator specs (consider an upgrade depending on system design), and analyze your 12v and 110v power needs before buying batteries, an inverter, and/or charger. Also you should consider a solar panel or two to keep the battery topped off. You should be able to charge the battery from the truck alternator with a small solar panel to keep it topped off, and run some small basic items like a coffee maker and lights with a small inverter.
If you are going to try to power a microwave or small AC, you are going to be into an entirely different level of power requirements, you will need more batteries, and will need to be more careful about sizing your inverter. You wont have enough roof space for solar to do anything more than maintain your batteries.
Good luck and feel free to email with specific questions once you decide what your system requirements are going to be.
