TOWING SAFELYMost of us flat-tow a vehicle behind out D, either with a towbar that mounts directly into the receiver or a ball mount.
The hitch receiver on the D is rated at 5000 lbs and most of the popular tow bars are rated at 5000 lbs.   However, even though your toad may weigh less than 5000 lbs, you may be subject to a catastrophic equipment failure resulting in your toad becoming disconnected from your coach.
Of course, it is imperative that the towing equipment be properly installed, inspected and adjusted.   Ball-type couplers pose special concerns.   However, no matter what type of system you use to tow four-wheels down, it is imperative that the hitch be within level specs of your vendor.   Most tow bar vendors require at most the towbar be within 3 inches of being level.   (Remember to check your towbar for level with your airbags inflated).
Towing out-of-level imparts significant forces on your towbar which could result in failure.   Also, if your towbar slopes down toward your coach, a sudden panic stop could cause the toad to jackknife.   If the towbar slopes up toward your coach, ordinary driving can place too much strain on the welds, bolt and attachment points which could result in failure.   "Towing level" is important whether you tow with a conventional towbar and ball coupler or one of the newer receiver-mounted towbars.   (Actually, it is MORE important with the ball coupler).
Step-up or step-down receiver adapters are available to correct an out-of-level condition.   These come in varying inches of correction, so make sure that you get one that will result in your towbar being as level as possible.   Note that if you get a different toad, you may need to get a different adapter.
I have seen many people towing extremely out of level.   Invariably, they tell me they have been doing this for the last XXXXX miles and never had a problem.   This is an accident waiting to happen.   I have also witnessed the failure of a towbar while in back of a class C towing a Jeep, which fortunately did not result in an accident.   This person was towing at least 6" out of level.   The rear arm failed internally and would not stay locked.   His Jeep was swerving all over the road crossing the center line several times.   After several miles of honking my horn, he finally stopped, and I pulled over also to offer any assistance.   After he inspected the problem, this fool elected to continue to tow to his destination, approx 165 miles away! I protested, trying to explain the danger to him and other motorists and that the other arm would likely break.   Off he went, but not before I got in front of him.
So, be safe and check your towbar for level and your towbar manufacturer's specifications.
I flat-tow a Dodge Grand Caravan with a Roadmaster baseplate and Falcon 5250 towbar.   I had to use a 6" drop-down receiver in order to tow level.   Roadmaster's specs require that the towbar be within 3" of level.
Submitted by Bob Cook