WordNet records no synonym and no antonym for whistle-stop tour. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a tour by a candidate as part of a political campaign in which a series of small towns are visited
“in 1948 Truman crossed the country several times on his whistle-stop tours”
Synonyms, antonyms and the broader and narrower relations for whistle-stop tour come from Princeton University’s WordNet. Full sources and licences.