If heading to GF, Polynesian, CR or WL, it's best to head to MK first and then, depending on which resort you're going to, walk, monorail or boat to the resort. You can also take a bus to WL from MK but you do have to get to TTC first.
If you are trying to get to the Epcot resorts (S/D, YC/BC, BW) you can head to DHS and then either walk or boat, without having to enter the park. The walk is about 20 mins, the boatride itself is 25 mins from DHS to Epcot, but there can also be some waittime for that as well. Or you can walk or boat from Epcot, but you do need park passes for that.
Want to eat at AKL?? Head to AK and transfer to a bus to AKL there. Or head to just about any park and take the AKL bus...all depends on the time of day and what parks are open.
The moderates and value resorts are a bit tougher to get to and from other resorts. You can take a bus from a park to those resorts. But if you're at another resort, you have to head to either DTD or to a park and then transfer to the resort you want to go to.
It's a good idea to leave at least an hour for travel time...especially resort to resort.