Slim-again - Picklejuice! Absolutely...If for whatever reason you don't/won't/can't drink sports drinks whether, it's THE fastest way to get electrolytes back into your system. a "shot" of picklejuice will almost nearly "cure" dehydration cramps "instantly".
Personally, I think it's a disgusting taste. However, I'm an event manager for a 2-day 150ish mile ride & the nearly 2,000 cyclists that participate each year would lynch me if I didn't offer it. I have done it in a pinch when I over-hydrated with water & nothing else (no sports drink or salt tabs, etc) on a solo ride. It's dirt cheap compared to some Hammer products with faster recovery & no stomach issues like changing sports drinks, etc.
I could go on & on, but if you google it, you'll find lots of support for this.
Sure a banana & some peanut butter & some sports drink will give you the same results but they take time to take affect (digest) and if you're behind the curve, it's the best/fastest way to get back to a safe place.
Now to the OP - if you've ridden 3k miles already (you didn't give time frame, but I'm guessing that's your '08 mileage), you likely have the legs/butt to do a solo century. I'd recommend a patch kit, quick-inflate system (CO2 cartridges) and a couple tubes. I'd leave the spokes & tires at home (but then I wouldn't have to walk more than a mile on my route to have cell service - an incovenience, yes, but better IMHO than carrying the extras - your call, no pun intended).
Regarding water & driving the route: Yes, drive the route & ride what you can of the hills. False flats suck when you're tired & mentally down at that 60ish miles point. Know the route, your mileage & your elevation if you can. When i was training for my running long distances (training for 1/2 marathon, "long" is a relative term) I'd stash water along my route the night before. My hint/tip for you is to "seal" it in some way - tape with your name (or something you KNOW is your handi-work), so you know if it's been tampered with or is safe & untampered, etc. Maybe that's not an issue for your route but for me it was a concern...
I don't ride with a camelback, but would if you don't own one, think about something like a deuter superbike backpack - hold tools, water, & other items...hot as hell on a longer ride though.
On your rest breaks...don't linger too long! Even in the hot heat, your body cooling down & then warming back up a few times is very difficult & makes the lactic acid buildup less tolerable.
Please post pics & let us know how it goes...I'm jealous of the scenery you get to ride through & wish you the best of luck. Sorry for the long rambling post.