'Good decision to increase your layout to the 5 foot width. With Fastrack a 4X8 is too restrictive and many passenger cars and engines would have problems with the 36 inch curves.
My latest layout is 5'X10' and has a double loop using 36 inch and 48 inch curves. My priority was to have a large "city area" set in the late 1950s. I only had 5 feet of depth available and built the benchwork/table on casters so that it could be rolled away from the wall for building and access to the track and trains when finished.
I wish that I had a 6 foot depth available...
