Phil. We could take a lot of pages to discuss the pros and cons. There are a number of things you will need to do to just about any brand to avoid damage from rocks and gravel. I saw a couple busted Jayco’s on the Gibb River Rd. Hadn’t been driven to conditions. Can I suggest you have a chat with the good people over here
https://www.caravanersforum.com/
regarding the requirements of off road vans.