Hi Patrice!
Thank you for bringing your question to the Disney Parks Moms Panel!
There are actually two Star Wars Half Marathons by runDisney.
The Light Side takes place at Disneyland in California and the
Dark Side is at Walt Disney World in California. You will be able to find course descriptions on the website. Of note, the Dark Side course in Florida is still being finalized, so look for that to be updated soon.
There is an area at both race finishes where families can gather to watch and cheer on their athletes. There is limited bleacher space but plenty of standing room. Generally, the celebration continues until about 10:00 - 10:30 a.m. Arrival time should depend on how long it takes your runner to finish. Spectators can sign up for Runner Tracking to help them follow their runner along the course and get estimated finish times. You can find that on your event's website, under the SPECTATOR tab.
I hope this helps! Please let me know if you have any other questions.