Was doing the ol’ what if on a flight to Oshkosh and found this Approach https://aeronav.faa.gov/d-tpp/2102/05319VA.PDF Below a screen shot of the surrounding area on the Enroute Chart on Foreflight with the pertinent airways displayed in blue and the OSH Feeder in magenta. Note says NoPT when arriving via the airways. 3000 to MDA of 1520 in 1.3 miles is kinda steep. OSH Feeder requires PT, airways don’t. ???