Three biggest problems people get into if they've not piloted anything larger than a pickup truck...
1. Turning wide
2. Running into overhangs
3. Backing up
You need to drive it around and get a feel for it. Like, a lot. Maybe some parking lot that's empty on evenings/weekends. Drivers who've not been in a long vehicle aren't used to how wide turns must be to avoid obstacles (curbs, barriers, other cars, people).
Unaware noobs also rarely know the vehicle's height. Yes, you need to know it to the inch... plus six just in case. Wiping a $5000 AC unit off the rooftop really puts a damper on travel plans. Smashing a $20,000 building overhang will ruin your year.
Also, backing up a box body, especially a 28 footer, is one of those things you don't just "know how to do". Even if it has a backup camera, it's still something you need to familiarize yourself with before hitting the open road.
Finally, if it's been sitting three years and/or hasn't been used regularly, it needs to be fully serviced before you start out. That doesn't mean just check the oil and call it good. It means a front-to-back fluid change, examination of belts and hoses, looking at tires for weather cracking, etc. If everything checks out, take a couple of 1-2 hr shakedown drives. If that checks out, a couple of overnighters to check living systems (driveway camping is fine for this).
Brad
