Yep, MN and DC was it.
I also seem to remember that once the Reagan campaign knew they had it in the bag, they quit running ads in Minnesota, I guess so Mondale wouldn't be totally humiliated.
Reagan didn't bother with MN at all, until the last minute. Air Force One was enroute to CA for election day, and made a quick stop in Rochester, MN.
Mondale won MN by a vote margin so thin that it was less than one vote per precinct (about 1,300 votes, I think). Several third-party candidates each had enough votes to constitute the winning margin.
There were persistent rumors of massive vote fraud in the Iron Range at the last minute to generate enough votes to keep from embarrassing Mondale completely. But, it wasn't worth investigating.