Blu-ray playback on a PC can be solved by using Cyberlink PowerDVD software. It updates over the internet to handle the newest blu-ray disks, I've never encountered a disk I couldn't play. That and Arcsoft are basically the only 2 pieces of software that work correctly.
Of course you need an HDCP compliant connection for blu-ray like HDMI. You can also use SlySoft AnyDVD HD which will decode the content protection on a blu-ray disk and play it over a VGA connection. You can also use it to rip blu-ray images to a hard drive for later playback if you have the space. Each rip is about 45GB. The AnyDVD software also automatically updates over the internet.
Newer projectors, especially the LCD models, don't really need to be used in a completely dark environment, they get brighter with every generation. Optimal viewing distance is 1.5 times the horizontal dimension of the screen, figure out your screen size from this based on your viewing distance then make sure the projector can throw that size image from your mounting location.
On our boat we use an LCD monitor. I have a mount where the swivel arm stays permanently attached to the monitor and slides into a bulkhead mounted bracket. We have a 15 inch monitor that swings into the companionway for use as a chartplotter, and a 24 inch 1080p monitor with the same bracket that can be swapped in and swings into the cabin to watch movies. Any monitor with an external power brick generally runs on 12v power, you can just wire it directly in to your DC panel.