we took our runabout in may and loved having it there, but we stayed at a monorail resort, so we just pushed it onto the monorail to get to MK and epcot. we drove to AK and MGM (drove down in the minivan with the hitch for the RA). we also had our 3 single umbrella strollers (with the connectors so dh and i could push a single and double) just in case using the RA was a huge hassle, but we only used those once, and found it much easier to use the RA.
on our first trip (when the kids had just turned 2), we took 3 single umbrella strollers with connectors so we could make a double and a single. worked out well enough, but we had both set of our parents with us, so plenty of adults to help out!
a word of advice: we bought the umbrella strollers specifically for that first trip, so the kids weren't very used to them....i think it made everything a bit tougher on all of us to not have "the" stroller that they were used to (we had a peg at the time). i also think the novelty of being in and out of these new strollers (as opposed to being strapped in to the one stroller) was also too much...too much freedom, too many options. if you're going to buy new strollers, make sure the kids have a chance to get used to them---it might help!
any other questions? i'd love to help if i can!