joemo, when you are at disney, go to the front desk/concierge that is in the lobby. they have this in all the resorts, even the values.
you can have them call for you or give you the number to call mears to set up your ressie with them.
it should be $14 per person for the roundtrip ride to universal from disney.
you are given a confirmation number and a pick up time at your hotel.
the little shuttle mears bus makes the rounds to the hotels for the reserved guests. it might take a bit of time as you don't know what other hotels will have pick up on the date you have chosen.
you will also be given a pickup time from universal for your return to disney.
last year, mears had 2 pick up times for the return from UO to disney.
i believe last pick up time was before UO closed. friends of mine used it.
if you go the mears route, take the earliest time for the morning run.
came back to add that if you use mears, you must set up the transportation in advance. the latest it should be done is the day before you want to use their service for UO