I just got back from a five day trip, with camping included. Here is what I carried:
A few small tool sets (Harley sets from over the years).
An air mattress and small Coleman electric pump.
A thin summer weight sleeping bag.
A two person tent.
Rain gear.
One set Under Armor (or suitable substitute) long underwear.
One summer jacket.
One set of HD rain gear.
Helmet (I wore it most of the time due to space restrictions).
Two extra pairs of jeans (I could have gotten away with one less, but I erred on the side of potential down pour)
Underwear for each day +1.
A combination of short and long sleeve shirts 1 for each day, again +1.
Socks for each day +1.
Shaving/First Aid kit (for toiletries and first aid stuff). (NOTE - get supplies that are approved by the FAA. That keeps their size down).
1 Pair boots (wore them), 1 pair cheapo sneakers (in case the bots are completely unwearable).
2 Pairs gloves. (I only used on pair through the whole trip, but they are small and don't take up any room worth mentioning).
2 Pairs glasses (day/night).
1 Set chaps (wore them).
Credit car and cell phone (with charging adaptor connected in tour pack).
Sunscreen for face and arms and chap stick for lips.
I pack the day before and use my saddlebag/tour pack inserts/luggage to make sure I don't over do it. I also carry one med sized duffle. If I am travelling alone, I put the duffle on the passenger seat. If not I put it on top of the tour pack. Be careful to not put too much weight on or in the tour pack or the front end of the bike will lift a little making the steering feel excessively loose.
I've been riding MC cross country trips for almost twenty years now, and have it down to a fine science (for my needs). Many of the things listed above may not be necessary for you, but this is what works for me. I usually don't use everything I take with, but it's there just in case.
Another option is mailing stuff ahead of your trip and mailing back your dirty clothes or finding a Laundromat and taking less and just washing clothes if the need arises (my female counter part likes the washing the clothes on the way, I don't want to waste my riding time in a nasty laundromat doing clothes).
This is what works for me. Try what you like, and disregard the parts that that aren't for you.
Hope this helps.