Since there are so many ideas.. another option would to be to just give each branch club a section and they can run their relay however they want.. something like:
Blaine, WA to Auburn, WA - Seattle Leafers
Auburn, WA to Vancouver, WA - Olympia Leafers
Vancouver, WA to Eugene, OR - Portland Leafers
Eugene, OR to Redding, CA - Southern Oregon Leafers
Redding, CA to Davis, CA - Sacramento Leafers
Davis, CA to Gilroy, CA - BayLeafers
Gilroy, CA to Santa Barbara, CA - Central Coast Leafers
Santa Barbara to Santa Monica, CA - Valley Leafers
Santa Monica, CA to Cerritos, CA - Los Angeles Leafers
Cerritos, CA to Oceanside, CA - SoCal Leafers
Oceanside, CA to San Ysidro, CA - San Diego Leafers
Anyway, just throwing out more ideas.