Well, after considering a lot of advice here and elsewhere, I decided against the "new" cheapo tandem and wnet with an old one instead, suitable for 250# me and the non-250# missus. A Scwhinn Twinn Sport 10-speed tandem, in good outward condition, needs cleaning and greasing, some truing of the rear wheel, lots of cute extras. Not the kind of tandem many purists and "real" bicyclists would give a second glance to, or even a first glance, but good enough for my humble purposes. Literature posted here said this bike weighs 52#, seems about right. It's not carbon fiber, but it's not $7,000 either, or even $1,000. And one thing you can say about these early-80s Schwinns, they don't change much with age.
The man said he was the original owner, and put maybe 1,000 miles on it. Original steel wheels, one original seat, fancy new pedals on the front, original ratcages on the back, toeclips all around. Drum brake rear hub. He replaced the front drop handlebars with some steel "up" handlebars, back before mountain bikes with flat handlebars became popular. 27x1-1/8 tires, I would guess, tread looked new but gumwalls were deteriorating, I'll probably replace them pretty quick.
52/39 front chainwheels, probably a 14-28 on the rear, chain never jumped once in any gear, including the highest when I really torqued on it. Neither wheel spins perfectly true, but the rear is worse than the front. Origianl steel rims, the man said. When I lift up the rear wheel and spin it, I can hear that drum-brake hub rumbling. The man assured me that that was just a characteristic of the drum brake hub, it sounds louder, and it's NOT the bearings problem I thought it was, he said. My money is still on me - it sounds like bearings to me, or maybe something inside that drum brake hub I'm not familiar with. I'll put those drop handlebars back on pretty soon.
Goodies: He still had the original drop handlebars, rear pedals, and a bunch of stuff like an original Pletscher rack, a Cateye computer (really old, might still work, needs battery), pedal EXTENSIONS he made for his 8-yr-old daughter way back when for the stoker pedals, a Zefal hp frame pump (remember those? So do I), the original owner's manual, a front pannier removable pouch, three 27xSomething thorn-resistant tubes, plus more. He threw it all in, $275 out the door. And it even fit in my Sienna.
Aside from the steel rims, my biggest worry is that noisy drum brake rear hub. Not really noisy, but if you listen you can hear it rumbling as it spins, which you can't on a normal hub. Anybody know if those are "supposed" to sound like that? The brake seems to work quite well, and if it were just quieter I'd be very pleased with it.
Well, what say ye? Did I do good for a 54-year-old fat guy who prides himself on averaging 15 mph around the (almost perfectly flat) paved bike path around Miramar Lake on a Sports Tourer?
(Isn't that a lot of slack in that synchronizing chain, or whatever it's called?)