Open to all, the Nationals is the best place to meet/greet many Basenjis and Basenji breeders.... I would suggest that unless you have a particular interest in a particular sport, you go to the conformation days. And one of the best (IMO) is puppy sweepstakes and Veteran Sweepstakes... then you see very young and very older...
That's a fantastic idea. Here is the schedule: https://www.basenjinationalspecialty.com/schedule/
For a spectator I think agility is hands down the most interesting. Unfortunately it's on the weekend so perhaps not the best for meeting breeders (if you care). This also doesn't seem to be Basenji only, so if you want to see Basenjis then probably not the best.
Lure coursing can be fun and there is a lure seminar on Monday. So Monday for that and Tuesday for Puppy and Veteran Sweepstakes?