If you are parked at Epcot, you can’t get to Skyliner without going through Epcot since the Skyliner station is outside the International Gateway. Hollywood Studios parking is okay since the station is right by bus stop.
It’s doubtful that a resort will let you park at hotel you aren’t staying without a dining reservation.
You can get to a Skyliner resort or to Hollywood Studios via a Disney bus or a chauffeured car or, in a few cases, on foot thus avoiding the need to park there. Then ride the Skyline./
This is not true. There are various ways to access the Skyliner without entering a park. Actually, the Skyliner is not within any parks. You can ride all the loops without ever entering a park.
Friends were at Disney Sorings, took a bus to Pop and ride the Skyliner from there.
OP, you will not be permitted to park at any of the resorts so it’s best to park at DS.