It's basically walking only, but it's under 15 minutes from any of the hotels.
Now if you're staying at DLH or PPH, technically there is transportation offered if you count the monorail. You would have to walk part way and then board the monorail in DtD and it would drop you off in Tomorrowland. But it's not really that helpful as transportation because it's not that much farther to walk to get to the gates, and sometimes it can take a while to wait for the monorail. It can be fun though. Also they're going to rip up that part of DtD and I expect the monorail will be affected at some point, but I don't know when.