I have attended motorsports events for 40 years and have it down to a science.
Are you required to wear the team shirts?
If so, black or white cropped trousers look better and are lighter to pack than jeans.
If not, I have taken to wearing maxi dresses. Might sound weird but they work fine at track.
Black and white patterned dresses when possible (floral, geometric, etc) with silver sandals and a black or white sun hat.
Minimal silver jewelry. Small black crossbody purse will be your best friend for a race weekend, to hold phone, money, ticket, credit card, lipstick or lip balm. Sunglasses.
For a four day weekend I would wear white jeans and black top & cardigan on plane with the sandals. As long as you don't spill anything on the jeans they can be reworn.
Three maxi dresses and a couple of extra tops plus maybe the pair of cropped black trousers in the luggage. Underwear, small bag of toiletries, job done. If you prefer trainers to sandals wear them on plane.
Don't worry about rain gear etc.; even if it does rain you'll huddle somewhere sheltered. Your hat will do. I used to take waterproofs and rain ponchos and all that folderal and never used. Take a clip in case you need to pull your hair up.
Everyone will be in the same boat so don't worry too much; it difficult to stay glamorous at the track.