You will do fine, with the plans you have already.
There are lots of places you can escape to with or without 4X4, as there are some amazing roads and regions to explore. If your idea of Quartzite n' such sound exciting, I would stick to those areas. Try Quartzite and go out and explore the region. For the last 8 winters I have spent them boondocking exclusively in the Mojave and Chihuahuan Desert.
As for the guns, you won't need them. You are more at risk in your home than boondocking. Crime Reporting Statistics proves this. But there are plenty of opportunities for shooting, so bring them if you would like.
Two Happy Campers are a great source of information as Melissa writes really well and they are happy to share. Each person/TC owner has their own needs and styles, gather information that best suits your own needs. Avoid those that tell you that you should do it their way.
There are some good articles on exploring in a Truck Camper Magazine, like the article;
Personal Safety in a Truck Camper checking the site or clicking on the author/byline you will find more information that might help you with your planning and execution.
Have fun!
b