The installation instructions tell you to mount the solenoid as close to the battery as possible. That would put it up front. I would put the rocker switch up by the solenoid and battery. Unless you want it on the dash somewhere. You will need to mount the remote control plug on the reciever plate next to the winch. Unless you get a second plug from Superwinch and mount one permanently on the front and rear of the van.
http://mediacdn.shopatron.com/media/mfg ... /14469.pdf
You are going to have a long cable run between the battery and the winch when its on the rear of your van. The instructions say to use 6 gauge wire. I would be a little suspect of that considering the length of the run to the rear. You will also have a long run for the remote control plug when the winch is on the rear of your van. I would increase the size of the wire to compensate for the length of the run to the rear.
It looks like you are going to need to find 2 different types of quick disconnect connectors. One for the positive and negative to the solenoid and another probably smaller gauge quick disconnect for the remote contorl wiring. Unless you go with the second remote plug wiring.
Keep us updated with the progress of the wiring job. It looks like an interesting one. I'm curious to see what kind of quick disconnect connectors you end up with.