I'm in the process of completing a layout expansion, which is 78 inches long a 40 inches wide.
Following Linn Westcott's excellent booklet on building model railroad benchwork, the train table is built and I'm very pleased with it. Also, I never had more fun building benchwork than I did building this table thanks to some extremely helpful advice and tips I got from my local train friends and fellow Forum members.
The expansion will have a yard with 3 or 4 sidings, structures and scenery.
Deciding what structures to have is one of my favorite things to do in our hobby.
Initially, I planned to have certain O scale structures that turned out to be way too big. What I have found is that the Plasticville structures I have are the ideal size for my layout expansion. I believe that Plasticville structures are considered to be between O and S scale.
In addition to being the ideal size, at least for where I intend to put them, I find that Plasticville has charm, especially when one has all the little details like chimneys and TV antennas, and they evoke nostalgic feelings.
I will post photos later as I finalize this expsnsion.