@eugene others more knowledgeable than me may chime in -- my understanding is there were changes to certain components in the drivetrain made by Triumph that caused them to make available an update kit, and it would be nice to know if the first owner of that 2005 had that installed.
Another challenge reported by some is the choice by Triumph (not uncommon in the motorcycle world) to route power for the headlights through the ignition switch causing pre-mature failures, and again, it would be nice if a previous owner installed a bypass relay of some flavor.
I hope it works out for you. Goldwings certainly have their place. Bet you'll love the Rocket.