How long has this truck been parked? Even with the drive shaft dropped you have the rear diff and wheel bearings that need to turn freely if you dolly the truck. If its been parked for years assuming those are going to go 1500 miles without trouble is a risk.
Changing the lube and checking the bearings improves the chances of making it but if its got a bad wheel bearing and you brought a dolly you're stuck until you replace that wheel bearing.
Have you ever pulled with a dolly? Backing a dolly with a vehicle on it means managing two distinct pivot points and can be extremely difficult to do. To cover 1500 miles you're going to spend most your time going forward, but it could be hard to go that far never backing up at a gas station or other parking lot.
Plus the dolly won't have any brakes. The trailer will probably have a surge brake system. Assuming your tow vehicle is adequate for the job you'll have a much safer braking system pulling the trailer even though the trailer will weigh maybe 1500 pounds more.
The cautions about rented trailers are valid, but the context is comparing to a rented dolly that could easily have the same issues. The rented trailer still wins as far as I'm concerned.
