We did a last minute trip, due to missing a cruise. One day to plan and had a great time. Orlando has an oversupply of hotel rooms that I really think it would be easy to find something offsite. I'm looking at doing something last minute Dec. 21 - 25, and even for Christmas week, there is tons of availability. We just like the vibe of the parks. On our last minute trip in January, we were able to get some good fastpasses, but selection was a little more limited. It was still well worth it do do that. We did three Disney parks, Epcot, Animal Kingdom, and Magic Kingdom. We also did SeaWorld and took the free bus and did Busch Gardens too (easy way to meet up with my cousin who lives in Tampa). We usually don't do a lot of table service meals at Disney, but you could easily call and check what is available. They have an app you can use to quick service to save time when there are long lines that I highly recommend.
My personal favorite for a good deal is a timeshare condo rental (love the extra space and love the resort feel and amenities). These IMHO offer a really good value for what you pay for them.
If you are mostly doing Disney, condos at Cypress Pointe near downtown Disney are a nice option and usually a very decent deal even if you do retail. You can do retail rentals from their site directly or thru a third party like Booking.com. Another one similarly priced I haven't done before but am trying on our next visit is Grand Beach. If you are going for a full week, and a Friday to Friday, Saturday to Saturday, or Sunday to Sunday, you might be able to find a really nice offsite condo on TUG2.met (marketplace) or on Redweek.com renting from a timeshare owner and saving even more.