Yikes, ended up investing over 350 man hours in this project but it was an enjoyable learning experience. I am still developing some of the supporting pages (like the Vehicles page) but the HPO catalog (both the online version and the downloadable versions) and the Checklists are complete.
This catalog includes all Highway Post Office routes and trips. It utilizes the new chronological Mobile Post Office numbering system with enhancements so that every trip in both directions receives a unique catalog number. This allows collectors to exchange and communicate the specific covers/cancels without missteps. The original route numbers are also presented to assist collectors who may already be familiar with the older designations. The online catalog also supports search feature, filtering capabilities, route maps, and many additional details. The catalog has over 5600 images of cancels, covers and route maps. http://stampsmarter.com/Learning/HPOHome.html
I hope that this will encourage people to explore this interesting part of US postal history technology. Please let me know if anyone has any questions, corrections, or feedback.