The Friendship Boats from DHS don't start until 8 a.m. I think the walk from DHS to the Swan is about 15-20 minutes.
If you get the bus from Pop to DHS before the boats are running, you can try asking the driver to drop you at the Swan. No guarantee -- I would do it, but I dont know whether every driver would.
Be at the bus stop by 7 a.m. the first day, until you get a feel for how things will work out.
Or take a taxi. It's only a few miles, so it should be under $10.