Welcome! You have a very good start there and I'm sure you will be much happier in it for 6 wks than you would be in a tent.
Right away I bet you will want to add door and hatch seals and give everything a good once over to be sure that you are weather tight, especially along the edges of any exposed wood and anywhere water can come in. With plywood construction any moisture that can wick into the grain will swell the plys and reek havoc with delamination. Also, it sounds like you are headed for some dusty trails, and the seals will help keep the silt that your TV (tow vehicle) kicks up out.
A water and dust tight camper can be dangerous to sleep in (CO2), and being in a hot climate, you will need to add some form of ventilation; at least a roof vent, if not a fan. Even if your door windows open, you want the heat to be able to leave out thru somewhere higher up, fresh air at mattress level is nicer. Passive ventilation from somewhere low inside the cabin with permanent/passive vents up high have been used to good effect, so that is something to consider if you haven't already.
Other than these things, a good mattress, water supply, and your regular camping gear (cooking and galley items, camp chair, some form of shade tent or tarp, and maybe a ground cloth outside your door to help prevent tracking dirt in)... I'd say you could be ready to camp in short order.
If you have time you might want to paint or stain some of the raw wood on the inside and in the galley. That will help make it easier to keep clean and prevent it from absorbing moisture from your breath and atmosphere; but that could come later. Actually, you might want to do this first before installing the seals.
I hope these suggestions are helpful to you and make your trip that much more enjoyable!
Around here we say that these things are never really done!
You will learn more about teardrop camping in one weekend then you will learn in a year of camping by yourself.
