Like a lot of questions that come up on here, this one is subjective. Some guys pack a ton of stuff while some pack very little. I feel as though I am on the "minimalist" end of the spectrum, so YMMV from mine...
Backpacks: are you meaning you have a pack you would deploy when you are off the bike hiking? Or do you mean you would be carrying some gear in a backpack while on the bike? If the latter, ditch it. You don't want to be wearing extra weight on a longer trip, especially if you will be getting on and off the bike a lot at stops and shedding your jacket. The backpack is uncomfortable in the long run and is inconvenient.
Oral intake: I personally never pack food, with the exception of a little bit of trail mix as an energy boost. In the eastern US you are never far from a gas station, restaurant, Quickie Mart, etc. If you get hungry, stop and buy something. If you are nearing your destination for the night, stop and get dinner before you arrive. I do have water though, always. Either a few bottles or a Camelbak bladder in my tank bag with the tube secured to a retractable ID lanyard.
Gear: I like to use a small sleeping pad, a bag, and if I need it due to weather or bugs, a 2 man Eureka tent. I generally just sleep without the tent and have gotten lazy lately and often don't bring it along, but I recognize I'm in the severe minority in this regard.
Clothes: on shorter (3-ish day) trips, I usually only bring one change of underwear, tee shirt, and socks (other than what I am wearing), a pair of flip flops, a pair of basketball shorts (which double as a swimsuit), a pair of long johns, a liner for my jacket, a neck gaiter (that doubles as a beanie hat) and a heated vest. The long johns, liner, and vest are for any colder unexpected weather. I wear riding pants, riding boots, and a riding jacket; with just my socks, underwear, and t shirt underneath. I change underclothes every other day, which may sound nasty, but who really cares? You don't really sweat a lot on the bike and even if you do, the funk stays bottled up in the riding gear anyway. And even if it doesn't, you are supposed to be a grungy, smelly bastard; you are on a motorcycle trip.
Tools, etc: I have the stock toolkit with a few tools removed and a few added. Strictly personal preference there. A spare master link. Wire ties. 12V air pump and plug kit. Multi tool in the tank bag. Never used anything in a ton of miles except the multi tool, wire ties, the chain adjustment tools, and the air pump and plug kit.
If you are staying in the US, and especially the east coast US, it really isn't possible to pack 'too little'. If you are on the road and you need something, you stop and buy it. In years past I've bought sweatshirts, a camera, sunglasses, and lots of underwear / tees (on my longer trips I sometimes just throw away the old tee shirts after they get stupid funky and buy a $6 pack of 3 new white ones). I think buying what you might need while on the road is a better option than sending back what you overpacked. Remember, a motorcycle is supposed to be fast, nimble, and light. You are supposed to live off it for a while with minimal equipment - I tend to think of it as an old cavalry horse with a bedroll tied to the saddle. If you find it necessary to have three bags, a trailer, and stuff bungeed to every available space, you are missing the entire point of motorcycle touring.
A fun, quirky resource is a pamphlet Aerostich puts out called "Lightweight Unsupported Motorcycle Touring for the Solo Traveler".
Here's my bike on a basic 2 day trip. Nice and simple, just the necessities:
Totally unrelated, but based on your avatar and your profile, I see you are a flight medic, nurse, or pilot.... could I interest you in trading shoulder patches, if your uniform has patches?