Any recent experiences taking the MEARS shuttle from Disney--->Universal?

[pittsburghmom]

My mom, sister and aunt are going with us to Disney next month. I booked them a room under our FD'ing PIN, and except for me needing to be there with them at check-in, we are pretty much parting ways after that. They want to do one day at Universal (we do not) and I am helping them with the logistics of it all. We will not have a car rental. From my research, I'm seeing that most opt to take the Mears shuttle. Do you still call the 800 number the night before and request a pickup time? Do you pay cash to the driver for the round trip? Any recent experiences would be helpful so I can write up a little "how to" guide for them. Thanks!!!