installing a double din is quite easy..pretty simply just an iso mount. Get your wiring harness done, antenna hooked up, possibly rcas and remote wires hooked up if you plan on running aftermarket amps...then use some plumbers strapping and super shallow screws that come with your head unit to mount the HU itself to the plastic air tubing for the vent above the HU.
took me about 30 min total for the install. super easy, no cutting or trimming at all
id stay away from the cheap ass double dins on ebay tho...stick with a good name brand. Pioneer, kenwood, eclipse, alpine etc. I personally run a Pioneer avic-z2 which also has an internal vehicle dynamics processor which can tell me speed, gforces (lateral or acceleration), slope, thru an internal gyro and GPS. Since my truck is on 44s (soon to be bigger) theres no way to have my speedo corrected so this GPS speedo on my deck is a great help.
As for the screen it will probably mount quite easily where your rear dome light is..unless ur trying to put it in the front in which case I recommend rivetting a piece of steel thats custom bent to the arch of your roof from the middle roof brace to the front and mounting the screen to that. Thats what I did on a previous install with great results.
