Note that there are two different landing strips for Newmarket, one with each of the two race courses. There's the July strip by the July course (runways 14/32) and 3 runways by the Rowley Mile (14/32 - not the same one as the July course strip - 10/28 and 18/36). They have major restrictions on use (e.g. not during races) and are strictly PPR - you need a briefing. The Jockey Club gets very upset if you frighten the horses (understandably - a good race horse almost makes an A380 look cheap). They are also a bit hard to see from the air. The July strip is so wide (70m) that it doesn't look like an air strip - the race track is next to it and looks much more like a runway!
The AFE VFR guide gives contact details and a map, and I'm sure Pooleys, Bottlang etc do too.
It's the best way to arrive for the races.