I truly hope that I'll have funds to support your cause, and one day do the ride myself. My grandfather passed away while I was in college from smoking related emphysema, so the ALA is a cause that is very near and dear to my heart.

A couple of ideas:

What about bringing lunch for all teachers? Like Chili? And asking for donations. Maybe enlist someone to bring sides?

How about setting a dollar amount to "sponsor a day of your ride?"

Some folks here used to ride rollers outside of stores (with permission). The "trick" would earn them donations.

Local bike clubs that might let you "lead" a ride and ask for donations?

Info Table/donation jar at a school sporting event?

Can your friends with the documentary plug your ride in their social circles?

Good luck!!

ETA: What about asking restaurants to donate a portion of the profits from a night? Lots do that.

With stores - try grocery coops and small places (or places like Whole Foods). I think they are more likely to support your cause than "big box retailers."