You mentioned Moab. BLM there is very strict as to where you stay. It's not just anywhere. It's mostly in established campgrounds. Problems occurred because folks were setting up camp anywhere. So keep this in mind.
http://discovermoab.com/blm-campgrounds/Also, for a single person, a Class B would be plenty big. Many 2-persons travel in a Class B and yes, full-timing. Not everyone needs a lot of space.
Agreed by others that if extensive siteseeing/photography is what you want to do than a small trailer such as a teardrop or Casita might work well for you and then you'd have a vehicle to travel in the boonies with.
Check out this blog. She's single and started years ago in the small Casita trailer she has now. She works for the national parks and has worked during Christmas at Amazon. She even has her budget published on her site. Read through it and you may learn some things and get ideas. There's a whole network of young RVers out there.
https://interstellarorchard.com/There a subgroup of the popular Escapee RV Club called the Xscapers. These are mostly younger folks and many are working from their RVs via the computer or working at odd jobs as they travel. They meet up as a group, usually boondocking somewhere, every so often to hash their experience out and have fun together.
https://www.xscapers.com/To answer one of your questions.... we have never and we haven't heard of anyone in our 16 years of full-timing who got broken into and we boondocked on public lands (national forest/BLM) 90% of our time..... and we don't carry. There might be more issues if parking on the streets. Criminals don't go out in the boonies to break in. They're looking for something quick and convenient.