Definitely do as others have suggested and take the bus to the Magic Kingdom and the walk to the Contemporary. Not only is it the most direct route, it will involve taking just one transportation segment (bus) rather than the three (bus, monorail, second monorail) that your original plan would.
It is actually about twice as far from the bus stop to the Contemporary as it is to the Magic Kingdom gate, but it is still a very short and do-able walk. Plus it will allow you to walk off a bit of the calories in advance of eating the yummy food at CM's!
If you'd rather not walk then your best bet is still the bus to the Magic Kingdom, followed by the monorail to the Contemporary. The Contemporary will be the first stop from the MK, rather than the 4th from the TTC (where you would have to change monorails coming from EPCOT)...just make sure you get on the Resort Monorail, not the Express.
Have a great trip!