Upon first becoming aware of the problem I pulled in to a convenience store and found even the lugnuts on one wheel too hot to touch. Jacked it up, removed nuts... couldn't get wheel off no matter how vigorously it was kicked. Wandered around looking for a heavy object to use as a sledge hammer; found big rip-rap rocks in a ditch. WHAM! That did it. Walked to a nearby residence and borrowed a big screwdriver; pried caliper open enough for free disc rotation (wimpy wet noodle Metro tools weren't up to that job). Got 30 miles down the road before some turd made me slam on the brakes; stuck again. Made it to a Menard's, jacked it up again, had to do both fronts this time in the 97 degree heat. Went in and bought a big C-clamp to free up the discs but found that even after many cycles of freeing-up/applying the brakes improvement was minimal. Freed them up and continued on... of course there was another turd that necessitated brake application so I did what I'd been dreading thus far: tried the e-brake. Not only did it stop well, IT RELEASED when released!
So the next 300 miles were completed with downshifting and e-brake only.
Full service in process at home.