dooftram: BikeLove2010 almost hit the target with the Schwinn Traveler, an '80's bike, but to my thinking missed by a decade. (No offense intended, it's still a Schwinn, and that company prided itself on a lifetime warranty for its frames, so still a good choice.)
The absolute best reasonably priced choice for your Dad is a fillet brazed '70's Schwinn in the 26" (seat tube) size. An article on Sheldon's website about these quirky models can be found here. It will not have the appropriate brazed fittings for waterbottles, but one can work around that issue. It will be a bike he will come to love.
I own (and ride daily) a Sports Tourer made in September of 1972. I spent half a year looking for one on the cheap for touring, and as they are not really collector's items, it was less then a $100. There is not a lighter, stronger frame out there now for less then 3-4 grand. I weigh maybe 170lbs soaking wet with a pack on a winter day, but I wanted a touring frame which could handle a couple of hundred pounds (of additional cargo). Researched this thoroughly, and though no weight limit as such is assigned to this bike that I recall, the fillet brazing (as is used on tandems), internal sleeving (essentially double butting), and oversized cromo tubing used on the largest 26" (seat tube) model makes it one of the most recommended rides for clydes (on the bike forums).
It has a tremendously long wheelbase, and almost an 18" chainstay. If you compare the geometry with Rivendell's top of the line touring bike, you'll see Grant Peterson may have liberally borrowed from these models. Stripped of the stupid kickstand (1.2 pounds), fitted with old Suntour bar end shifters, scrapping the (chromed) steel toe clips, and absent the pie plate it weighs in at 24 lbs, (for the 24" model). I could go on singing praise to this bike, but I won't. I want to head out for chanterelles and boletes on my Sports Tourer. Instead, here's the best place I've found to seek one out. They have some bikes for sale, but if you search the used bike pricing guide, it generates a listing of people selling old rides at (generally) reasonable prices. Cheaply sometimes even. They don't have much right now (with a search for an ST), but I didn't extensively search for the Super Sport model, for example. Of course, try the other normal channels too.
Happy Trails! (Roy Rogers was Schwinn's spokesman...only thing he'd ride other then Trigger was a Schwinn!)
p.s. Oh yeah, if you find one stock in good shape as I did, it came equipped with a hefty butt-delightful Brooks B-15 leather saddle. (Seat post is gas pipe, but short so swap it out if you choose for a cromo... Stock centerpulls have the reach for 700C wheels, though the stock wheels are cast(!) aluminum and with double butted spokes and as strong as steel. I swap 700C's onto my ST and that sheds another couple of pounds... And the stock gearing on the ST was the widest for any road bike, so perfect for loaded touring or a big person. Derailer sucked though...)
