I sold an HO drag strip and some have asked that I post pictures here for ideas. Basically it is a HODRA legal 1/4 mile track. The outer lanes are wired for return roads. There is about 1.250 between the racing lanes. It is built in four 7' modular sections. The first section is free standing. Each subsequent section rest on a saddle of the previous section and only requires legs at the end. See photos below.

http://photos.hobbytalk.com/data/511/medium/Drag_strip_4.JPG

Another picture

http://photos.hobbytalk.com/data/511/medium/Drag_strip_2.JPG

Last picture

http://photos.hobbytalk.com/data/511/medium/Drag_strip_3.JPG