In reply to Andrew W:
I've done quite a bit of cycle touring.
My number one would be, get a Brooks saddle. It may seem counter intuative, but the softer the saddle, the worse the pain. Brooks saddles are harder than normal, but this means you slide around more on it, thus not costantly having pressure on the same part of the anatomy.
Other than that, never use a backpack, always panniers (sorry if that's self evident, but don't know how much you know about touring basics)
Start off easy and build up (I always go for a 30 miler for the first couple of days to work the legs and the arse in).
Hotels are much easier than camping. We used not to book, which makes for a more flexible tour, but abroad, in a strange town, hunting a hotel room on a Saturday night at 10.PM when all you want is some food and a beer is no fun. Now we work out the route in advance and pre-book all the hotels.
Don't kill yourself. Set sensible limits. I notice your route is about 60+ miles a day. That's doable, but in my experience, cranking out that sort of mileage is not very enjoyable. It all starts getting to be about covering distance rather than enjoying the ride.
Have a rest day. I'd go for one a week.
Don't worry about rain. You'll get it, and no matter what you use, you'll get wet (though that said - I now use a carradice poncho - heavier than your cheap, flappy plastic or nylon ones, mudguards and gaitors, and I've stayed the driest I've ever been - only a little sweat build up inside).
Never delay eating or drinking. If you are hungry, stop and eat. If you are thirsty, you should have stopped and drank about half an hour ago.
Go with a friend. There's nothing like chatting as you ride along. It's good for setting a pace, also. By that I mean, it slows you down rather than speeds you up. If you hadn't already guessed, I prefer to enjoy the ride.
Don't take too much gear. I find about three t-shirts, a single fleece, two pairs of trousers, about four pairs of sock, a lightweight, windproof jacket, raingear and a hat. Regarding underwear, I tend to take three of pairs of nylon, sports type underwear and wash the ones I've been wearing nightly - same with the T-shirts. T-shirts and trousers should be sythetic, so they dry easily. I also take one pair of jeans and a couple of cotton t-shirts, just to relax in. I take one pair of cycling shoes, and a pair of crocks for wearing off duty.
Take a camera (small one) and take lots of pictures. You want to remember it.
Learn how to fix your own bike. Luckily, I know bikes like the back of my hand, so I can fix them no problem. If you don't, watch some youtube videos, read up on the internet, take the plunge and dismantle your bike and put it back together again. There is nothing worse than something breaking and you having to phone a taxi to take you to the local bike shop, assuming it's open.
Toolkit - allen keys (make sure they cover all the various size bolts on the bike) chain splitter, tyre levers, crank remover, small adjustable spanner, spoke tool, puncture repair kit AND a couple of spare inner tubes.
Had four punctures in a day once. If I'd just gone with the innertubes, I'd have been screwed. Take some zipties. They are invaluable in a bind for fixing a lot of things).
Enjoy. There really is nothing like cycle touring.
I've probably missed out a load of things, but my tea's on the table, so have to go.