Has anyone done the 6-hour Bike Ride in the Vinho Verde Region excursion while on the Duoro River cruise? We’re not avid bikers, but are certainly fit and exercise regularly. The description says it’s 13 miles and is for people who bike regularly, which we do not. Is it difficult or is Tauck just trying to weed out people? We’ve been on 12 Tauck tours and understand their “activity levels and pace” gradings and know that a “4” might really be a 2 or 3. We’d like to do something active and the only other excursion option was a vineyard walk w/cocktail making. Thanks!