Hi Joanna,
I love Port Orleans Riverside, it's such a pretty resort and the boat ride to Downtown Disney is lovely and relaxing!
There are 4 bus stops at the resort so you're never very far away from one but most people also like to be close to the main building where the lobby, restaurants and shops are. The best buildings to be close to all the amenities are either 14, 15 or 18 in the Alligator Bayou section or Acadian House or Magnolia Terrace in Magnolia Bend. You can see a map and lots of other good information at
www.portorleans.org and requests can be made by calling 407-934-6000 a few days before your arrival, please remember they are just requests though and not guaranteed!
You will be able to get back to POR from the Contemporary where Chef Mickey's is located but how you do so depends on what time the parks close on the day of your reservation. If Magic Kingdom is still open, or within about an hour of closing, then simply use the walking path from the Contemporary to the Magic Kingdom bus depot where you can catch a bus back to your resort. If MK is closed but Epcot is open then catch the monorail to Epcot and transfer to a POR bus there or finally, if neither of those are an option, catch a bus to Downtown Disney from the front of the Contemporary and transfer there. If none of those appeals then taxi cabs can be found at the front of the resort!
Have a fantastic trip,
Jo