For planning my trip to Spain, I have found posts from user "Road Trip Spain and Portugal" on Youtube to be very helpful. I will be in Barcelona and Madrid. His videos explaining transportation are very good. For instance, How to Get from Barcelona Airport to Central Barcelona explains four options in detail and then at the end shows a chart comparing them. In a video about getting from Madrid airport to Gran Via area (where my RS tour hotel is located), he mentions a free bus that runs along Gran Via from Atocha train station to Moncloa bus station and there is a separate video on that. In all my researching, I had not come across that (but I don't have the most recent RS book yet). See the video for details because he mentions it could be discontinued. It is probably of interest to any RS tour going to Madrid, and the tour guide probably provides the information, but knowing now is helping me plan our days after the tour.
There are many videos that have great information for tourists of all kinds, not just those with vehicles and not just about transporation. Good information about various sites, neighborhoods etc.