I upgraded my Giant Escape R2 with a Surly Cross Check frame (let me know if you wanna buy my old Giant frame. I'm in Misawa and could Black Cat it to you
) Surly's are very nice, but I wouldn't pay that kind of money for them.
If this is something you are planning for next year, your best bet is to keep an eye for an old school steel frame your size and build it up from there. There are some very nice Nishiki, Panasonic, and other touring oldies out there that will be every bit as good as a surly (minus all the braze-ons, but you can work around that) for a fraction of the cost.
If I was overhauling an old bike, I would replace the drivetrain, upgrade the wheels to 700c (which, them being smaller than the old standard 27" would give you a hair more clearance for bigger tires) and maybe replace the brakes if they are not long enough to reach the 700c rims. I would have done this myself but out here in the far north most of the used bikes are mamarachis.
PM me if you wanna tour the deep north. I have a three day shimokita peninsula trip I wanna do.