Not sure where you sail, but, at a minimum, I would add:
spare aka brace bolts with zip ties
spare rudder pins
hand pump
spare line
anchor
multitool?
marlinspike?
I also file a "float plan" letting someone on shore know my planned itinerary and estimated time of return.
I use an iOS app called Checklist. Here's an export without the nice formatting:
Communications Float Plan
VHF
Phone
Beacon
NavigationChartplotter
Battery Charged
SD Card Loaded
Handheld GPS
Batteries
SD Card Loaded
Chart
SafetyPFD
Knife
Whistle
Marlin Spike
Multitool
Ditch Bag
Rudder Pins
Aka Bolts
Zip Ties
Light
Spectra
HealthFirst Aid Kit
Food
Water
Sunscreen
Lip Balm
BoatHatches Sealed/Drain Plugs Closed
Anchors
Bilge Pump
Sail
Peddles
Paddles
Trampolines
ClothingDry suit
Hat
Gloves
Glasses
Go Pro CameraBatteries
Mounts
Blank SD Card
Check out this thread:
http://www.hobiecat.com/forums/viewtopic.php?f=71&t=55811