Hi, I would also recomend a Brooks leather saddle, Champion Flyer (with sprinngs) or B17 (without) and the Schwalbe Marathon Plus tires, my wife and I both use 700x35c, they cant be beat for reliability and comfort.
As for a bike here is a site that has some pics fullyloadedtouring.com, it will give you an idea of the different tipes used for loaded touring. I ride a hybrid and my wife a fitness bike both aluminum, good bikes, and they din't break the bank. We use them only for touring and long day trips, we have a couple cheap city bikes for everyday.
Also make sure you have low enough gears, (your knees will thank you), we use 42/32/22 up front and 11-30 on the rear, we can climb almost anything with this setup.