Make sure all your lines and blocks are in good working order. Your boat is cleaned and does not leak. Check your spars are in good condition and straight and check your tiller and foils are in good condition. Basically make sure you have done all you can before the event to minimise risk of gear failure.
Don't put an inspection hatch in for the simple purpose of carring food - not needed. You can usually find a rib to carry it for you or the race boat will often take bags if you label it clearly. You'll also be surprised at just how much food/gear you can carry on board. I tape spare drink to the mast and have one bottle in the back of the cockpit (attached with some elastic). I have choc bars and extra hats etc in my buoyancy aid pocket or taped choc bars to my boom. This way I survice 6hour+ days on the water at events.
I make a point of never using new kit for a big event [clothing sails gear sheets]. You never know what problems could arise. At least test them out in a couple of races. New lines /sheets may be ok but wash them first in soapy water to get rid of the manufacturing chemicals- this improves grip in cleats and your hands.
I still wouldn't put a port in unless it was needed for a major repair to the boat. Storage to my mind is not a good reason to cut your boat open to fit a port.
I wouldn't recommend tying a bowline to the mainblock, as it's hard to set your maximum out, and if you drop it, it's hard to grab under tension. I like a stopper knot and 1 foot of line after the stopper to keep a hand on
I always seem to have trouble with rivets at regattas, so my tip is to replace all rivets with monel. Even brand new spars can suffer from loose fittings if the spar is old stock. Corrosion between the aluminium and the stock ss rivets is relentless, so swapping to the monel rivets will fix the problem permanently. (About $1 each)
I have tied a bowline before and it has come undone, and this has never occurred with the figure of 8 stopper knot. Also, I agree that an inspection hatch is not necessary and is just another place for the boat to leak.