Have you been to WDW or DL before? You said you have been to California Adventure, but what about DL?
Trying to see MK or EP in one day - and expecting to see everything is unrealistic. If you are okay realizing that you won't have time to see all the attractions or do everything - then one day a piece is an okay plan. For two days - I think adding parkhoppers is too expensive.
If you have been to DL - I might actually suggest two days at EPCOT - and be sure to buy your tickets in advance so you can get a FP for Soarin one day and for FEA the other day. TT you can ride single rider as you are adults. On the first day - focus on all the rides and attractions in Future World - and do ALL of them. And then maybe start walking around the countries - starting in Canada. Book a dining reservation some place for lunch or dinner. On the other day - plan to focus more on the countries - but realize that area is not 100% open until 11 am - so things like FEA is open earlier and is the bakery in France - but those are on opposite sides - so you need to plan this. I'd suggest repeating a favorite in Future World first thing - then having a FP in the morning for FEA around 10 am. Then see the countries starting in Mexico (a little backtrack from FEA) - and proceed around. Make sure you see the movies, some of the live performers, and the singers in America. I strongly recommend the drummers and the mime. One of the days - plan to stay to see the fireworks show.
MK and DL ARE different - but if you are familiar with DL - given your limited time - I'd focus on different parks at WDW.
If you have NOT been to DL - then one day at each park is the way to do it if you want to save money.
If you are traveling to FL JUST for 2-3 days at WDW - as an FYI - I find that to be a waste of money. The travel costs are too high IMO - given the amount of time it takes to see all of WDW. WDW takes 4-5 days to see a large chunk of it. And
ticket prices decrease on longer stays. So - I'd never recommend anyone spend high travel costs to see WDW in 2-3 days. Now - if this is just a couple of days at the park as part of a longer trip to FL or if you are just driving in for a couple of days from someplace just a few hours away - okay maybe a 2-3 day trip is worth it.
You HAVE to buy tickets in advance and get FP's in advance - and maybe make a dining reservation in advance if you can afford a TS meal. And you need to look at map and make a plan for your day if you want to get your money's worth at WDW. Really.
I personally know two adult couples who have recently been to Disney for a one day trip to one park - and both - despite my urging - didn't get their tickets in advance, didn't get FP's, and didn't discuss what all they wanted to do in advance. Both couples told me afterwards that I was right and really regretted not pre-planning. They were overwhelmed with how much there was to do and couldn't believe the lines. They thought I was a hyper planner. They found themselves frustrated with lines and unclear what to try to squeeze in and spent a lot of time just wandering and feeling like they weren't getting their money's worth.
. In my opinion, two or three days are nowhere near enough. Do what you can afford - if one day at each park that you choose is what you can do then you'll still have a great time.
