I have a Nishiki Cresta frame with components that are older than what you suggest that I had planned to tour on, but never actually toured on it. I doubt I will every bother to set it up and tour on it but see no reason I couldn't if I really wanted to. It would have to be because I really wanted to ride a retro bike or for so reason other than purely logical ones though. I think at least slightly newer bikes offer a lot more.
I did do most of the Southern Tier (San Diego to Pensacola) on a 1990 Canondale Crit bike that had almost all of the original components still on it other than a different cluster and crankset. I really enjoyed that bike. Seven speeds, super crisp shifting, completely trouble free and great memories of riding in my younger years. Add to that all the conversations of folks who stopped to tell me about how they raced on the same bike (or rims, or whatever) back in 1990. Something about that bike just makes me happy, I can't walk past it without touching it.
The only changes were to get a lower gear range. The crank was a triple with the big ring removed so effectively a ultra compact double (39/26) with a 12-28 cluster. It was kind of a weird set up, but it worked well for me and was adequate with the ultra light camping gear I was carrying (14# base).
Oh, yeah the fork wasn't stock either, but that was only because the original one was destroyed in a crash. Otherwise It still would have had the original.
I also did an on/off road tour on a 1990 Canondale mountain bike that was pretty close to box stock. A few parts were replaced over the years as they wore out or were broken, but generally with stuff similar to what was available at the time the bike was built. Some other stuff might have been changed for personal preference with period stuff. The bike was a joy to ride for the type of tour I took it on. I used Kenda Slant Six tires and they rolled okay on the road and worked great on the dirt.