Best way to get from WDW to Universal

[crassmonkey]

We have decided to add two days at Universal to next years WDW trip. We don't want to rent a car as we will be spending the rest of our vacation solely on Disney property. So what's the best/cheapest way to get from our resort (Pop Century) to Universal and back on those two days?

 

[nikkie876]

Car seats..

We have 2 kids in Car Seats, 1 in a booster and 1 in a convertable. We won't have them with us, the older one will be okay without the booster but are shuttles/taxis required to have carseats for the younger ones?