I too recently was wondering the same thing.
The reason I bought mine, was to use it on occasion to trek around up in Colorado in places I wouldn't dare to take my new truck.
For me that’s about a nine hundred mile trip, one way.
I found the owners manual, for my Cherokee falling apart, in the glove box when I bought it back in November of 2007. I carefully went looking for towing information in it, as it is in bad shape (the manual), and found this:
Recreational Towing
(Behind Motorhome, etc.)
Use the following procedure to prepare your vehicle for towing.
Selec-Trac
Caution: It is necessary to follow these steps to be certain that the transfer case is fully in N (Neutral) before recreational towing to prevent damage to internal parts.
1. Shift transmission into N (Neutral).
2. Shift transfer case lever into N (Neutral).
Note: The FULL TIME light will stay on.
3. Shift transmission into D (Drive) and make sure there is no vehicle movement.
4. Turn ignition key to the unlocked OFF position.
5. Shift transmission into P (Park).
WARNING: With the transfer case in N (Neutral) position, the vehicle could roll unexpectedly. The parking brake should always be applied when the driver is not in the vehicle.
6. Attach vehicle to the tow vehicle with tow bar.
Caution: Do not use a bumper mounted clamp-on tow bar on your vehicle. The bumper face bar will be damaged.
Command-Trac
Caution: It is necessary to follow these steps to be certain that the transfer case is fully in N (Neutral) and that the axle is completely disengaged before recreational towing to prevent damage to internal parts.
1. Shift transfer case to 2H and check that the PART TIME light goes out.
2. Drive vehicle 10 ft. (3 m) rearward and then 10 ft. (3 m) forward to make sure the axle is disengaged.
3. Shift transmission to Neutral.
4. Turn off the engine with the ignition key in the unlocked off position.
5. Shift transfer case lever from 2H to N (Neutral) position.
6. Shift manual transmission into gear or automatic transmission into P (Park)
WARNING: With the transfer case in N (Neutral) position, the vehicle could roll unexpectedly. The parking brake should always be applied when the driver is not in the vehicle.
7. Attach vehicle to the tow vehicle with tow bar.
Caution: Do not use a bumper mounted clamp-on tow bar on your vehicle. The bumper face bar will be damaged.
I don’t think you will get a definitive answer to your question as to "safe towing distance" because many have different opinions about what works and whatnot. Reading some of the post (concerning towing) on this forum has left me a little confused.
But, if they were not meant to be towed, I don’t think there would be a section in the manual titled “Recreational Towing” telling us how to safely do it. In my opinion, Recreational Towing, implies "many" miles of "towing".
I don’t know if this has been posted on this board but I found it useful in making my decision concerning towing mine.
It was taken word for word from my owners manual and mine is a 1988 Jeep Cherokee Pioneer.
Hopes this helps