Mears can do the pickup from any resort hotel. It is $14 per person CASH ONLY roundtrip.
Just dial "0" from your room phone or any WDW house phone the night before you wish to go to Universal and/or Sea World.
When the WDW operator answers, ask to be transferred to Mears. Then tell Mears which hotel your staying at, where you want to go, and about what time. They will give you a pickup time at your resort.
You can either schedule a return time when you make your Mears reservations or wait and call the number on your return ticket 2 hours before you wish to be picked up. Mears will give you a pickup time and you will be picked up at the same place they dropped you off.
The same as airport transfers, it is very possible you will visit other resorts both going and coming back.
We are using Tiffany's van service for our Universal transfers at $70 + tip, but there are 6 of us, so it is less expensive.
Carol