Hi, Elisabeth! Thank you so much for your question!
The Goodings Supermarket at the Crossroads shopping center is just over a mile from the Downtown Disney Marketplace. It is definitely walkable, but anything you might buy that will melt is going to melt in the hot Florida sun and it's kind of a long walk with heavy bags. Of course, walking a mile or more to me sounds like exercise, and I'm opposed to any form of exercise that doesn't include a handshake from Mickey Mouse at the end!
You can take the boat or a bus to Downtown Disney, walk to Goodings, walk back, and then take the bus or boat back to Port Orleans French Quarter. Alternatively, if you are spending at least $50 on your groceries - and at Goodings, you can easily get to the $50 mark - Goodings will deliver the groceries to you for $25. They are delivered directly to Port Orleans French Quarter between the hours of 4 and 7 PM. They are delivered to bell services at your resort, and refrigerated for you if necessary. All you do is order the groceries online at
www.shop.goodings.com - and if there is something you need not on their list, you just call them and they will see if they have it available. The $25 delivery fee would be well worth it to save my lazy self from having to do all of that walking!
Have a wonderful vacation, Elisabeth!