5rv wheel chocks removed.....check
Landing gear Up.....check
Emergency pin installed....check
5vr wheels spin freely when jacked up off ground....check
Truck rear wheels spin in gravel-----5vr doesn't move. IF it was any other truck besides that RAM I would say not enough truck :B
Only 2 things come to mind
5rv rear stabilizer jacks still down and digging in
Have you tried to move in reverse.
Got trapped in wet soggy grass one time and couldn't move....trucks rear wheels just spun.
Loose gravel can be a bugger sometimes with pin weight of 5vr