On bad weather days (there can be some REALLY bad winds and rains)
and on hot days, the trams would be a poor choice (or cancelled.)
And, after dark, smaller vehicles on the narrow well-traveled roads would be a hazard.
Remember that if they did build a separate roadway, they'd have to make it wide enough for opposing vehicles to pass each other.
(Consider that there are lakes right alongside the current roadway.)
(Maybe the -so far- "vaporware" that is the "gondola.")