Are you carrying luggage or is somebody bringing your stuff in a car. Sounds like an awesome excursion, either way.
Minimal luggage. Pretty big fanny pack. Stayed at hotels, ate out at brewpubs & convenience stores... Just over 300 miles for 4 days..
Off bike clothes in dry bag
2nd set riding sock & undies
A couple buffs
Camp towel - spent most of weekend in jersey pocket
Pretty robust first aid kit
Family size cycling lube - not chain lube ;-)
Ball cap (for rain under helmet)
Charger cables for phone & garmin
Rain jacket strapped to outside.
Tools in frame bag under top tube - wallet & phone in there too.
3 bottles - one on down tube (water), two in bags on either side of stem (typically gatorade, which I've had enough of for a while..).
Plenty awesome, even though today was a pretty soggy day all around.