Good point Dave for sure!! That is why I want to start at that end of the layout. If I have to have it above the window sill I will because my wife asked if she can keep books, videos, games, etc on the bookshelves. My construction will have to make easy access for her, which is maybe the best reason for making the layout high as John suggested! 
She donated the land for the right of way, so we will have to give her all the easements she desires!
Reminds me of a true story my maternal grandmother told many times. When the PRR wanted to build a branch line from the Connemaugh Division at Freeport up over the hill and back down to Butler, the railroad people came to her father and said they wanted to build across part of his farm. They were willing to pay a certain amount, but great-grandpa said he was willing to let them have the right of way for free, because he could get his farm goods and lumber he cut transported with ease.
Funny, once the line was abandoned in the '80s and they were building the bike trail, one farmer took the local rails to trails to court claiming the right of way reverted back to him afterwards. He even dumped truck loads of rock on the right of way to block bikers. He lost out, and has now passed on. Now his son, who is a friend of mine, raises turkeys right up next to the bike trail, and it is a nice stop for city bikers to get a bit of a view of farm life. 
