There is a shell garage near knockhill so can always fuel up there. I suppose it is really up to you in terms of what to take. If you have track wheels then take them and am sure someone will let you put the other wheels in there car. Might be worth taking some spare oil but apart from that then I don't think you really need anything else other than a helmet. You are £115 for a member slot. Just make sure your brakes are in good shape.
I am sure the seasoned track experts will be along with good advice
Chris