I take Amtrak to Orlando regularly from Sarasota because I am unable to drive due to a medical condition.
I pay $32 or $33 RT on the Mears Shuttle from Amtrak to the Disney hotels. I usually stay at Pop when I do my solo trips. It may be a couple bucks more to some of the other hotels.
If there are two people, it would be cheaper to do the shuttle r/t for them as opposed to a cab. Mears dispatch is just a couple blocks away from Amtrak so they usually arrive pretty quickly.
They will let you make a "reservation" usually, but they won't plan to pick you up until you call them when you actually arrive because trains are notoriously late.
Mears contracts with cab companies to do alot of these trips so they may very well send a cab for you. Also, on return, I suppose it could happen, but I have never had to share a ride with anyone coming back the way you do the airport.
Hope that helps.