I actually worked as a Vice President of Marketing for Evergreen on the helicopter side of the house for several years. Only one B747-100 was converted for fire fighting work....and it was not used all that much for fire suppression as Evergreen wanted a lot of money for such work and a competitor operating DC-10s was much cheaper with regard to their charter rate. So the U.S. Forest Service as well as other domestic fire fighting agencies (such as the California Dept. of Forestry & Fire Protection) tended to call the DC-10 guys first. The Evergreen 747 "Supertanker" also saw some international use as well fighting fires at various locations. The company spent buckets of money developing the Supertanker and I do not believe it was ever a profitable business for Evergreen on a stand alone basis.

Evergreen as a fixed wing and helicopter operator no longer exists. And I'm curious to know if their aviation museum in McMinnville is still open. If so, it's well worth a visit.

BTW, that 747 you saw which now serves as a rooftop waterslide attraction was actually flown into McMinnville Airport (which has a 5,420 foot runway) following its retirement as a freighter.