Never found the answer for what to bring so I literally try and bring every part and tool I can fit in the truck. Anything you leave at home you'll need.
I bring a lot spare parts wise, including extra sails, rigging, rudders, I have them and they don’t take up much more room. It’s probably a 60 mile drive just to get a shackle where I sail so I can’t risk it.
As far as non sailing gear for a regatta, a shade tent makes any time spent on land a lot nicer, make sure it’s well staked and not obstructing others
I have something like that, but I found the cloud to be more handy..
If the list is rather long you have to actually mark each item, otherwise you go over all the list many times but with less attention each time and may end up skipping an item. Or maybe i’m a bit obsessive compulsive... Anyway, Wunderlist app worked better for me