Absolutely! How long it takes to get between parks depends on the parks you're going to. For example, Epcot to the Studios is about a 20 minute walk or a boat ride. I'd allot at least an hour, maybe more, to get anywhere else though, just in case you have to wait a while for the next bus/monorail. A nice way to plan park hopping is to go to one park in the morning, take an afternoon break, then go to another park in the evening.