The Parklife Cities: Skylines DLC introduced some new tourism options, including sightseeing buses:
The Sightseeing Buses are a new transport feature that acts as a new form of attraction for the tourists – and for an occasional citizen too. With Sightseeing Bus Tour Tool the player can create Sightseeing Bus Tour lines which will have Double Decker buses travelling along the lines... To gain the best results it is a good idea to create the Sightseeing Bus Tour line through high appeal areas.
I currently have one sightseeing bus line hitting several separate areas, each with high appeal (showing in pink) across two map tiles. Yet at best a handful of people ride my sightseeing bus line, so it's often operating at a heavy loss.
How can I get more tourists to ride my sightseeing bus?
Where the description says "create the tour line through high appeal areas", does it mean the entire line should be within one large high appeal area, as opposed to connecting several large high appeal areas built somewhat far apart? If so, then is there a substantial benefit to using these buses over the walking tours?
Is there a max length the bus line should be?