The voltage from the alternator runs between 12v-14v... Does that sticker on the back of your monitor list what voltage range the monitor itself can handle?
You probably can get away with tapping your monitor into the 12v running from your computer's PS. That voltage is regulated and clean. Thats what I did with my display.
Is that a datalux monitor? Didja get it off ebay?
What did you decide about powering your machine from the VX? a DC-DC PS or inverter?
As far as mounting.. You can do several things. This is what I would recommend and samiliar to how I did mine:
Take apart the display from the case. Chop the case up so you have enough left of that nice factory bevel that goes around the screen, and the holes that are used to mount the LCD module/inverter/etc to the interior of the case. Cut out the factory dash area to overlap with the chopped up display case. Epoxy the LCD casing to the backside of the factory dash. Then fiberglass between the two, bondo, sand, etc. You probably can just get away with bondo.
Now you can just screw the actual LCD module to the back of the factory dash, where the original holes in the casing were.
This may or may not work depending on how the unit is assembled internally but this is how i did mine.
When I was first working out possible solutions in mounting a different type of LCD module in where the stereo is, I was considering on just purchasing a few generic stereo installation kits and using the pieces from that.
Try not to install these type of components with the assumption you won't need access to them semi-often. Though I've only had to take out my screen twice for some backlight inverter mods, I've taken out the CPU at least 20-25 times already. Of course, being in a one year timespan thats not terribly bad.