Just Google: rv delivery drivers
You'll find the names of several delivery companies. If you have your own authority (DOT #) etc., I'm not sure what the process is. Otherwise, you'll need to sign on with one of the delivery companies and jump through their hoops regarding equipment, age and appearance of your truck, insurance, damage deposit, etc., etc., etc., and of course DOT physicals, background checks, and more etc.
I enjoyed being a dedicated delivery driver with Jayco's delivery division ('Jet') back in the day. When those deliveries became too few, I signed on with another company that paid less per mile but said they'd find 'back hauls' back towards the Middlebury area; they never found even one
. In short order, after a few west coast deliveries and many promises, I was thousands in debt and I threw in the towel.
I guess I enjoyed it while it lasted, but I really didn't make any money at it. I'd only recommend someone do this if they really didn't need the money and wanted to see lots of miles of roads.