Hi Erica,
Welcome to the Disney Parks Moms Panel! I can totally understand being on a serious budget - that would describe my entire Walt Disney World vacation planning experience!
You may certainly purchase a resort refillable mug. We use these mugs to refill our drinks at our resort hotel although I have seen other guests take them into the parks to use for water. On our last trip, we did not have a dining plan, so we bought the resort refillable mugs separately for everyone in our family. Our girls refilled them at least three times a day at the resort hotel.
With respect to your second question - yes, you may certainly dine at other Walt Disney World Resort Hotels. We always make
advanced dining reservations at some of our favorite restaurants outside of the theme parks - 1900 Park Fare at Disney's Grand Floridian Resort & Spa, Chef Mickey's at Disney's Contemporary Resort and 'Ohana at Disney's Polynesian Village Resort. Before or after your meals, take some time to explore the resorts and visit the gift shops.
Erica, be sure to download the
My Disney Experience Mobile App so that you can see the best transportation options between locations. Since we rarely drive, we love to use the "Get Directions" feature on the app to determine our best route to each location and to see the estimated transit times between areas!
Magic, memories and Minnie Mouse hugs,
Donyell