I relocated mine under the hood a while back and even did the install for a member here on the forums.
The two big advantages of the project is the fact without the solenoid box, the winch sits lower, allowing more air flow across the radiator. Another advantage is that the solenoid is out of the elements, prolonging the life of the winch.
Basically what I did was mount the solenoid to the CAI firewall with a pair of self taping screws. Alternately, The member I did the project for did not have the CAI and we managed to mount the solenoid to the firewall back in that same area. Hopefully he can chime in and provide pictures of it.

From there I ran 8' battery cables from the winch body to the solenoid. There is enough space to run the cables in a gap by the passenger headlight. Then I ran the cables I already had from the solenoid to the battery. Unlike the photo above, I ran wiring loom making the cabling under the hood look much cleaner. From there you can stop. But I decided to go two steps further. Firstly, I decided to extend the cables for the "key" to the solenoid and run them inside the cab to the storage bin to the left of the steering wheel.

Secondly, I ran cabling from the key inside the cab to the my switch bank. That way I can use the "Key" if I am recovering myself and need to be out of the vehicle, or I can use the switches (one for power and one for in/out) if I am being spotted. Really the project was not that difficult, just a little time consuming splicing the cables for the winch key and switches