Hi Angela,
Yes, the Disney Dining Plan is accepted at the
Coronado Spring Restaurants including the Maya Grill, Pepper Market and Cafe Rix. The Maya Grill is a Table Service meal that uses one entitlement per person. The other two are Quick Service locations that you can redeem your credits for meals or snacks.
In response to your other questions, the buses don't run from Resort to Resort. Meaning, you'll need to take a bus to either the Transportation and Ticket Center, Downtown Disney or a Park to switch to a bus to another Resort. The fastest way would be a taxi (which is less than $20). Otherwise, you should plan on heading to Hoop-Dee-Doo Revue and Mickey's Backyard BBQ on a bus bound for Fort Wilderness if you are in Epcot, Hollywood Studios or Animal Kingdom. You would head over to the Resort buses and instead of getting on one going back to the Coronado, you'll get on a Fort Wilderness one instead. If you are in the Magic Kingdom, you should get on a ferry boat to Fort Wilderness. For the Spirit of Aloha show, which is in the Polynesian Resort, you should take a monorail from the Magic Kingdom or Epcot and a bus from the other Parks.
Hope this helps and have a wonderful vacation,
Kaylene