Transporting a 3D printer does not require special precautions.
Obviously you should package it to protect it from damage (but this depends on the mode of transportation and how sturdy your printer is; if you are just placing it in the back of your car with no chance of it bumping in to anything, no packaging is required at all).
It might be wise to secure the carriage(s) in place so they can't move around, but I would definitely not bother with unplugging anything (apart from the mains power, naturally). Leaving the motors plugged in means they will provide some holding torque, which might be advantageous to keep your axes from sliding around.
Dust is not too great of a concern, as 3D printers can handle it (to some degree) thanks to the seals included on linear bearings.