The easiest part would be Silverton to Lake City over Cinnamon Pass. There is a choice going up outside of Silverton at Animas fork. the way up and over Engineer Pass is steeper with steep switchback turns, not as bad going the Cinnamon pass route. I've not done it on the Strom, and my skill level is low, but I would try Cinnamon Pass. In my mind, the hardest parts are the steep 180 degree turns of the switchbacks. These may not be hard for your skill set, or perhaps your fiance would get off on these turns, there aren't very many.