There actually are three monorails.
Two of them run in opposite directions in a loop around the Seven Seas Lagoon outside the main gate of the MK. The resort monorail runs clockwise around the lagoon and stops, after leaving the MK, at the Contemporary, the Transportation and Ticket Center, The Polynesian and the Grand Floridian before getting back to the MK. The express monorail runs counter clockwise in the same loop but stops only at the MK and the TTC.
The Epcot monorail runs in a loop between Epcot and the TTC and makes stops only at those two stations. There are no resorts on the Epcot monorail line. You can switch from the Epcot monorail to either one of the MK monorails at the TTC. If you catch the resort monorail, your stops will be--in order--the Poly (it's even a short walk from the TTC, as noted above), GF, MK and CR, then back to the TTC.