For module construction techniques, suggest you have a look at the guidance available from the various modular groups. No need to reinvent the wheel. Track planning is up to your own imagination. Here are some links to get you started:
http://www.trainweb.org/ttat/ttat_module_spec.pdf
http://www.trainweb.org/Nation...ers/NCTStandards.htm
http://hirailers.org/PDF/Stand...raight%20Modules.pdf
http://hirailers.org/PDF/Stand...0Curve%20Modules.pdf
http://hirailers.org/technical.htm#Module Building Techniques