Being off-site won't ruin your trip. Your trip is what you make of it. You could put my family in a cage to sleep and we'll still find a way to enjoy and make the most of it. With that said, I will say we enjoy Deluxe. We got our first "taste" of it last year and LOVED it. We stayed BC and being so close to EPCOT was a real treat.
Honestly, your planning will need to be tailored a bit, but you can certainly pull it off. You're going to have to be on the ball with your ADRs and have backups planned for FP+. The only park that will see a phased closure will be MK. MAYBE AK, given the new Pandora, but it's such a behemoth of a park that I can't see the park itself closing, just the land.
You're gonna wanna get out of the parks for a while and take a break, especially if it's as hot as it was last year. At MK, Contempo, Wilderness Lodge, and GF are all wonderfully decorated. You can easily go there and spend a few hours touring the decorations. GF often has an orchestra playing and it's soothing to just sit down, listen and enjoy the view of MK.
At EPCOT, head over to BC, YC, BW and Swan and Dolphin.
Make sure you do Disney Springs during the week. During the weekend it gets CRAZY busy. Remember, this is geared toward locals so everyone heads there on a Saturday/Sunday. Despite it being (mostly) open, there are still some walls that lead to a bunch of pedestrian traffic (and traffic in general)... but i'd totally recommend going to DS. We have a yearly tradition of going and getting the free peppermint bark chocolates at Ghiradelli.
That sounds like the perfect way to start your day.
