If you have a local shop. Go there and ask them what a good way to put in a box in your truck would be. Dont let them talk you up or sell you anything but sometimes having a local opinion is helpful. Trucks are really tricky to put boxes in. Ive seen some pretty cool ways of doing it though. people building boxes, putting them in the back of their truck, Cutting circle holes into the back metal and pushing the subwoofer surround into it. So just the sub is in the actual cab and everything else in the bed.
this is an extreme case but kind like this
http://image.sporttruck.com/f/10758591+w750+st0/0807st_16_z+truck_bed_sub_enclosure+trim_panels.jpg
or the little back area.
http://www.pickupspecialties.com/Subwoofer_boxes/Truckboxcopy.JPG
or maybe if you have room under the seat itself and you could put a box under it.
IDK trucks are hard...
if you have wired one amp, youve wired them all. Two channels can run passive. four channel can run active. You just run the pos to battery. Neg to chassis. Run speaker wire to speakers.
Gotta find a place to mount your tweeters. The passive xovers that come with components make things easy. You just run your +/- speaker wire from your amp to your passive x-over and then it has 4 screws for you to attach your speaker wires too. 2 screws +/- to woofer. 2 screws +/- to tweeter. It chooses your crossover points for you
http://i.ebayimg.com/00/s/NTU2WDc0Mg==/z/w2IAAOSwd4tUIK48/$_12.JPG