Disney will publish a road closure map as part of the event guide. It is not currently available. (The link is basically
https://guide.rundisney.events/ but right now it still shows Princess 22)
So assuming similar courses (which is likely with minor tweaks) Friday is the 5k and it is self-contained in Epcot. You should have no issues driving to Contemporary or MK Parking.
Saturday is the 10k. If they use the same course as last year, it goes from MK parking lot to Epcot. If you are going to drive to Epcot, you should be okay if you come in Epcot Center Drive from World Center Drive or from Buena Vista/Disney Springs side. If you're coming from the west/Western Way side, you will need to avoid some stuff on Buena Vista near Studios/Boardwalk.
Sunday is the half, which last year also went from MK to Epcot, and the course stayed pretty much west of World Drive. If you Drive to HS, you will have no issue, since you enter HS parking from Osceola.
Here's a link to a site with last year's maps so you can see. Of course, the courses are not finalized til about a month or so from the event.
https://noguiltdisney.com/rundisney-wine-and-dine-2021-course-maps-event-guide-corrals-and-more/