8 weeks. Dude. Where's the tour?
Anyway, i rode a similar style solo last year though only 12 days.
Rode with 2 changes of summer cycling clothes and did okay.
For 8 weeks you might think about 3, you can go a week and only wear stuff twice between actual washes.
I'd suggest that you get a winter jersey with a full zip. (Descent makes great ones.) This can also double as a camp jersey but if it gets regular wear you'll feel like your'e never out of it. Also pack a midweight capaline shirt and tights and some camp-pants. The capalines are light and compressable and some of the lighter travel pants are supre light and very durable. And make sure you have a pair of warm socks for camping...
My other suggestiong is a 'sil-tarp' by Inertia Designs. I have the small one that weighs 2-3 oz and squishes into a waterbottle. Get the large size and use super super thin guy wires (i used extra strenght floss but it dosn't last) and make a 'tent' with your bike in the middle. If you get really excited imitate the Topeak tent (too heavy) that uses a bike as a pole and cut the tarp to cover the seat, bars and then you...
I usually tied mine to a picknick table and to the ground. It meant i was crawling but had enough to read a book, write with a dry notebook and cook out of the rain. Also to stay out of the sun when i needed to.
The other things i'd never leave behind
My Jetboil.
They really are that good. No. Wait, they're better. Super fuel efficient, easy and tight space compatable. I've cooked right in my lap! I lived in a friends attic and cooked off of one for weeks and the fuel efficiency is great. Only reason i'd leave it behind is if i had to go regular gas... And probably not then.
My titanium spork. Incredably geeky i know. But i don't carry anything else. It fits in the liner of my jetboil and nothing gets lost.
Petzy Zipka. The headlamp with the retractable string that holds to your head. Teeny tiny yet runs on AAA's, can double as a bike light or helmet light and i've commuted with it on fresh batteries.
Emergen-c The little packets from the health food store, good vitamins and electrolytes and super tiny packable.
Aqua-Pur. The water purifyer tablets... You never know what nastys are in the laundry room tap your filling that bottle from...
No-rinse camp soap. For hair body or clothes a no rinse soap can't be beat.
Hand sanatizer stuff. Mix a tube of equal parts hand sanatizer and hand lotion. That in itself makes a good bath without burning your skin. I'd get to camp, strip and wash the... parts. Saddle sores are bad. It also kept me from smelling too bad.
Tire-flys. GEEK PART #1 But with just small head and tail lights these are invaluable in night, early morning or dark and stormy rides. I keep them in a baggie and apply (with 29cent valve adaptors) when needed.
A handlebar bag. I didn't have one though i keep water bottles on the front. I'll never tour without. I stopped at every side-road to avoid getting lost, stopped to get my camera, stoppeed to put on sunscreen, stopped constantly. I'd probably pause to do these anyway but there's a difference between pause or rolling pause and stop, swing the leg over, dig in the bag etc...
And of course, ziplocks. 1 galon ziplocks...
The other sugg. i've got from mine and others who've posted is to prep some spare gear and leave with someone who can mail them. You could mail your smelly's home halfway and get fresh clothes, have the spare wheel overnighted and save $100's. Even tent parts, stove... whatever...
Good luck...!