We're a
Disneyland family going to WDW for the first time in a decade this summer. We have 6 day passes and reservations to double up at MK and DHS (DHS in case we don't get a boarding group the first day and MK because you have to end your trip at the castle!)
Our plan is to park hop to Epcot the second DHS day.
Also, although a lot of MK rides have similar ones in Disneyland, we love checking out the small differences in the versions of these rides. There are things like riding side by side on Splash at MK, but riding single file on Space, the different haunted mansions, and how the dark rides are extended or shortened. And we LOVE getting to ride Disneyland favorites that are gone: People mover, Carousel of Progress and the Country Bears. Even if you go to Disneyland a lot, the MK is fun (but it would be better with a Matterhorn).