Our bed is a little bigger than queen size, and it will become a pull out couch someday, we are going to finish the trailer on the outside, camp in it a few times and then make changes as it seems neccessary. The queen bed is about 10 to 12 inches off the ground.
The upper bunk is 30 inches wide by 72 inches long, the lower bunk is 30 inches wide by about 63.5 inches long(basically the width of the trailer) and only about 6 or 7 inches off the ground, it will be were we store our axe and our camping chairs.
As for power nothing planned right now, I'm going to use battery operated led tap lights for each bunk with one big tap light in the middle. If in the future I need or want power, I'll build a power center at the front of the trailer, that way I only need to drill one hole into the trailer for power entry, If I do do the power I will probably do something solar based, or just buy a little quiet generator, as we never go camping in camp grounds that have ac hookups. I like the TV idea, maybe in the future I don't think the wife would go for it, yet.
I hope to have the ceiling and roof in tomorrow... I'll post pics when done.