According to the April Issue of Motorhome Magazine, 1992, where they towed the Explorer behind a Safari, make sure the hubs are in the unlocked position, the transfer case is in the neutral position, the transmission in neutral, the key in the ignition to unlock the steering wheel.
The owner's manual has concise instructions for towing.
Curb weight for the 4 door version = 3937#, 2 door version = 3816#.