Being more of a newb to the pricing of stuff, but still a shopper for it, I would agree with above. You would probably get more by parting it out. Like for instance on your layout. I personally wouldn't want the complete layout, but I would definitely be interested in the track. Same goes with all the rolling stock, loco's, and sets. Hopefully come tax time I will get to spend some money towards my collection of stuff, and the 2 engines at the bottom (the UP and CSX) would be something I would look at buying. I am just trying to give you a buyers perspective on what you have there, so I hope this helps you out some.
BTW, if you are looking at selling this stuff, and parting it out, let me know what you would ask for the loco's I mentioned, as well as some of the rolling stock...lol