They are doing them now. You do get to go on any ride you want, as many times as you want, although I think there may be a limit with RotR. You go through the FP line most of the time, although a few rides have special entrances -- Haunted Mansion, for example, has a cool back entrance. You do not skip to the front of the line, you wait just like you would with FP. If you go now while there is no FP, the wait is minimal. Normally, you can go to as many of the parks as you want and time allows, but I do not know if that is still the case with no hopping. If you change parks, the tour guide drives you and you go in/out back ways, cutting down on travel time. When we did it, we stayed in MK and gave the tour guide a list of rides we wanted to ride. It was not every ride in the park, but it was most of them. We only did one show. The tour guide took our list and planned out the best approach, and we got through everything on the list in 7 hours. You definitely do not run out of things to do, unless there are a lot of things you don't want to do or you pay for extra time. If they are doing fireworks when you go, you can plan the tour to end when the fireworks begin and the tour guide will leave you in special VIP seating for the fireworks.
Some people say the tour guides are walking FastPasses, which can be the case depending on the tour guide and how much you engage with them, but our guide tried to give us interesting facts and tips and really enhance the experience. They say they can pick you up at your resort to start the tour, but I highly recommend meeting them at the park so that you are not wasting tour time with travel. I also recommend eating a big meal before you begin and not taking a big meal break during the tour.
It is expensive, and for that reason we probably will not do it again, but I am glad we did it once. It was nice to get to ride a lot of rides without a lot of waiting. It was also nice to not have to plan or make decisions -- we left that up to the tour guide.