only 3 hotels have direct monorail access: contemporary, polynesian and grand floridian.
the monorails come fairly often, maybe every 7-10 minutes or so at the most.
the main hub is the TTC. from the TTC, you can take a monorail that goes to the front of Epcot (going over the park a bit). you can also take an express monorail that only has 2 stops: the TTC and Magic Kingdom or the resort (local) monorail which goes between the polynesian, the grand floridian, the magic kingdom and the contemporary and back to the TTC