I live in Lihue, HI , on the island of Kauai and am an avid surfer. I just wanted to share my take on the venerable TW.
I have performed some minor modifications to my TW to suit my needs to get my self and my surfboard to the local breaks and to access difficult, out of the way spots. I love this bike and it is perfectly suited for my purposes. I can go 55 mph with a short board surfboard without any difficulty. I don't even feel the presence of the board.
Mods so far ( everything sourced from Procycle in Springfield, OR, except when noted):
Clarke 3 gal tank
Cee Bailey's Windshield
Procycle front motocross style fender
47 tooth rear sprocket
Waterproof rear lockable storage box by SeaHorse ( Amazon)
Black paint (Home Depot)
Surfrack (Carver Racks- Oahu, HI)