I suggest you go visit the section of this site with coop pictures. I studied these for a couple of evenings and took ideas from different designs. There are some recommended sizes and heights for roosts and nests that I tried to abide by. My roost is located about 24" off the litter and even with the bottom of 2 large flap style windows. The girls jockey for position every night to be in front of the windows. I think they really like looking out as it gets dark.
I also modified the waterers so that they hang. I placed it and the feeder (also hanging) so that I can reach in and swing it to me without having to walk into the coop. I did the same thing in the run. My nests open from the outside as well. I can do all the daily water changing and egg gathering without having to enter the coop. Sounds nuts but I can't tell you how many times I am in a hurry to leave for work and run out there to change water. The non-entry method means I won't be getting poop on my shoes and therefore don't need to change them every time I go out there.
Oh, one other design I did was designed the chicken door (the one they use to get in and out of the coop) as a guillotine style with a cable and pulley system that runs all the way out to the exterior of the run. I can open and close it daily without having to go in the run or coop.
Just a few ideas to make daily routine simpler.
