Correct, no direct way.
Walk, monorail, or resort boat from GF to MK (Gold Flag launch) (walking or monorail will be easiest/quickest, the boat goes to Poly first then to MK so you’re backtracking/spending extra time than needed).
Then take the separate resort boat from MK to WL (the Red Flag launch). A bus from MK to WL is also available as an alternative option.
Have fun!