Depending on where you stay, you may not need transportation for the race. If you need it, though, from
runDisney's FAQ:
Complimentary event transportation will be provided by the Anaheim Transportation Network throughout the
Disneyland® Half Marathon Weekend to participants who are staying at select Disneyland® Resort Good Neighbor Hotels. Shuttle buses will depart from select Disneyland® Resort Good Neighbor Hotels to the Disneyland® Resort East Esplanade Shuttle Drop-Off area every 20 minutes continuously throughout the weekend during scheduled Disneyland® Half Marathon Weekend events. A ticket will be given to participants the first time they board the shuttle that they must save for use over the entire Disneyland® Half Marathon Weekend. Transportation from Disneyland® Resort Hotels will not be provided as they are within walking distance to all of the Disneyland® Half Marathon Weekend events.
You can view the
final race instructions for the bus route information.