An analysis of words in Midwestern Airbnb listings includes a connection between McMansions and fishing:
Anyone can catch a walleye with a few bucks’ worth of basic gear, some practice and a little luck, Roach said, though that doesn’t stop some Midwesterners from dropping the equivalent of several years’ salary on boats, McMansion-grade ice-fishing trailers and sophisticated electronics designed to better target the finicky fish.
Follow the link for the trailers and you can see large ice-fishing trailers. I assume that is the primary use of McMansion here: these trailers are large. They offer a lot of interior space. Maybe they are mass-produced or architecturally dubious but the size of these trailers is bigger than just a little ice fishing hut.
At the same time, the use of the term suggests that the ice-fishing trailers are over the top or unnecessary or undesirable thing. McMansion is an evocative term that is usually linked to negative judgments.
The lingering question here: is the large McMansion trailer a worse choice than a more modest ice-fishing dwelling?
(This is not the first time McMansions have been linked to transportation. See earlier posts here and here about McMansions and SUVs. Those ice fishing trailer need a sizable vehicle to tow them into place.)