Hi, I'm in the middle of building the Central Midland. Right now, I have the benchwork done, roadbed laid and just finished all the track. Trains will run (with occasional derailments... arg...) using a single DC power pack and one connection. No scenery, but I have scattered some buildings that I acquired around.
I'll figure out how to post some pictures. Here are some recommendations that I'd make from where I am in the construction:
1) The book is from a while ago, so plywood and 1x6x8 were the building materials of the time. I used wood throughout the construction. If I was to built it again, I'd use foam board for the yard and the large flat area where the diesel maintenance area is located. I almost did, but I had a bunch of plywood laying around and figured what's the difference. Well, first time some of the plywood warped pretty badly, I had to get some recut some more.
2) The layout is switch-heavy. Depending on your perspective, not everyone is needed. If you priced out all the track (using Atlas sectional track, it's around $1,900.
http://www.atlasrr.com/Code100web/pages/10029.htm For example, the switches on the back mainline aren't really necessary, although the do add some variety. Also, I cut one of the yard tracks in order to have some room for a bit more buildings/scenery.
3) The diagram uses sectional track, but I used flex-track. I highly recommend it for two reasons, first, it's easier than assembling all those sectional pieces. Second, while I was religious in laying out the pieces of wood, you aren't going to be perfect and the flex allows for some variation in following the wood. However, you'll most likely have to solder the flex pieces together, which was tough for me with the constant curves on the mainline. Second, it provides for less connections - each connection is a place where the cars can derail.
4) Although I'm using DC right now, eventually I'll use DCC, so that will simplify the wiring a lot. I'm still trying to figure out where I need insulators in the track and where I don't. The diagram has them everywhere, but that's to support a block system.
5) The layout doesn't provide a lot of flat area for a town scenes. I need to think about where I'm going to put what, it's doesn't flow naturally. Also, the idea for the scenery seems to be a wire mesh that you lay scenery on. I plan on using foam board and arranging it to cover the scenery. I haven't figured out how to do that yet!
6) I made the mistake of shrinking the layout's width by 20 inches, to fit into a specific area in my basement. I thought it would no problem, but the underground loop on the right turned into nightmare. It's about a 20" radius, but only because I changed where it comes out of the tunnel on the right hand side. I'll find get a picture of that too. I don't have any problems with the loops being tight, the engines I have seem to work fine. My problem is that some of my soldering wasn't the best, so cars derail on specific spots. I'm fixing them, filing stuff down, etc but it's a pain. I'm glad I didn't use sectional track, because I'd have about 3 times as many connections to worry about. It's like a huge puzzle when you use sectional track. Also, even with section track, it didn't always fit like the digram. In some places (notably the cross over with switches on the entry to the yard), not everything fits perfectly.