This is the fastest way. You walk across to the swan and to the sidewalk along the river between it and DHS to DHS.
There is also a bus route, I don't know which one but I think it also goes to Blizard Beach and you let the driver know you want to goto FG for golf. I'm not sure how it works on the return but I would guess you ask at the Desk of FG and they will have a bus routed for a pickup.
The best way using WDW transpo would be to get back to DHS, and catch the POP bus there. The walk from the Swan to DHS will be in the 15 minute range for most people (plus add 2 minutes since FG is on the far side from the walkway). If you time it right, catch the boat as it leaves the S/D dock. The boat ride is 7-8 minutes to DHS.
If you're golfing at night & DHS has closed more than a hour ago, you'll need to take a bus from the Swan to the MK (if still open) or DTD, and transfer there to a bus to your home resort.