We always take the boat to MK. If you drive, you have to park at the TTC and then take a boat or monorail to MK, just skip a step and take the boat. LOL We have also taken the boat to the poly, had breakfast, then monorail to MK.
To epcot, we like to take the monorail, but it takes a while because you have to go to the TTC either by car or boat then monorail, switch to the monorail to epcot. This takes longer, but the kids like it.
We drive to the other parks and our 2nd day at epcot. When the kids are tired and/or sleeping at the end of the day, it is much easier just to plop them in the van and then go straight to our site.
Oh, BTW, if you visit downtown disney, DRIVE. We have tried it 2x and both times, each way took well over an hour. There are a million stops on the route and the wait between busses is really long.
Which, leads me to a question about driving and parking at DTD. We have a tradition of hitting DTD our last day for shopping and lunch at the Earl. Last time we drove there, we were in a popup and managed to find 2 spots nose to nose that we could pull through (although it was real close). Next trip, we will be in our big camper. Where can we park? Is there parking for RVs? Or, should we just park in the overflow lot at FW and deal with the bus?