Hi, Jo Ann! Thanks for writing back!
Boy, I remember the stroller days! Having little ones certainly does allow for a great work-out!
So here is the deal with the strollers for the Magic Kingdom. You will have to fold them up prior to boarding the bus which can get a bit tricky logistically with juggling kids, bags, coats, eats. However, if you drove over to the Magic Kingdom, you would have to fold your stroller to get on the tram from the parking lot to the Transportation and Ticket Center anyway, so you may as well do it for the bus and save time.
Buses can get busy, especially at park closing, but even if you have to wait for another bus, it is still quicker to take the bus than to drive to/from the Magic Kingdom. For Epcot and Hollywood Studios, you are going to take the boats. And you can always walk from these 2 parks back to the Dolphin, especially if your little Mouseketeers are cozy in their strollers! I think when you see the proximity to Epcot and Hollywood Studios from your resort, you will see how it is closer to walk or do the boats vs. driving. I know it sounds weird, but when in Disney, the roads are not always the most direct route.
I hope this helps. Feel free to
write me back if you have more thoughts or questions!