Just to add to Kim's excellent description of circuit and track racing, the busway (Lakeside Way) is currently closed around the back of the Theatre, Film and TV department and the Ron Cooke Hub due to the road surface deteriorating to the point where individual bricks are popping out of the road when buses drive over it! (1) I think there is a diversion round it, I shall try to remember to go in that way tomorrow and check.
Be careful using Sat-Nav, as you can wind up on the wrong side of the circuit on an unmade road - today's school visit saw one minibus do exactly that.
If driving, it's probably best to head for the Grimston Bar Park & Ride on the A1079 and follow the signs for the Sport Village from there.
I'm probably going to be around from about 12:30 on the Sunday, so if you have any problems come and find me. I'll be the one in a bright red York Sport polo shirt (unless it's raining, in which case I shall be wearing a black York Sport waterproof waterproof!)
Your friendly York Sport Cycling Attendant!
(1) It's a brick paved road, laid in an area with a very high water table and around 8 buses an hour running along it! I'm amazed that it has lasted this long, to be honest.