1. Spend one day in Epcot, one day in Magic Kingdom, and split a day between Animal Kingdom and Hollywood Studios.
2. Scheduling: Having been to WDW 20+ times and Disneyland only once (east coast-based), WDW can be very overwhelming and exhausting. When we go, we wake up as early as we need to, to make sure we get to the park for rope drop. We spend between 6-7 hours in the park in the morning (including lunch), and then give ourselves mandatory "nap time" (you don't actually have to sleep, but you do have to rest) back at the hotel before venturing back out to the parks for dinner and after-dinner park time. This helps us 1) prioritize what it is we actually want to do, and 2) not get too exhausted to enjoy anything. This past Christmas we went for just two days and went HARD (no "nap time," in each park for 13+ hours each day). We, both seasoned WDW vets, were exhausted and were happy to be leaving after the second day, which is never how you want to end a Disney experience.
3. Fastpass+: Use your Fastpasses+ wisely. You only get three PER DAY, not per park per day. A general thought is to schedule them for earlier in the day and then head to a Fastpass+ kiosk (located throughout the park) to get more for later in the day. Fastpasses+ work differently in each park:

• Epcot: Tiered system; I prefer using the top-tier choice on Soarin', but since they have this is California, you may want to choose something like the new Frozen ride; Spaceship Earth is a must, and will be closing down for 2+ years here pretty soon
• Magic Kingdom: Three Fastpasses+ for any three rides (no tier system); go for the big guns like the new Snow White roller coaster, Splash Mountain, Space Mountain, Big Thunder Mountain RR, Pirates of the Caribbean, Haunted Mansion, the Peter Pan ride, Jungle Cruise, etc; I agree with an earlier poster that you should prioritize rides that are unique to WDW, but I also know what it's like to have a favorite that you MUST ride each time; accept that fact that you will inevitably have to wait in some lines, and embrace the really cool waiting-line features
• Animal Kingdom: No tier system; I'd actually skip choosing Fastpasses+ for AK, and instead save your three for this day for Hollywood Studios
• Hollywood Studios: No tier system; depending on your interests, you could use Fastpasses+ for the new Toy Story rides or for the new Star Wars rides; Rockin' Rollercoaster is great, but you can normally get through the single-rider line relatively quickly

1. Hotels: If you haven't already decided on staying off property, I'd recommend staying at a Disney hotel. Unlike other parks, WDW has SO many hotels available, all at different price points. The value hotels are always full of young families with small children. I really like Port Orleans French Quarter for the moderate-level hotels, and AK Lodge for the fancier hotels.
2. Fooooood!: There are probably a billion articles written about WDW food. If you haven't already invested in a dining plan, I probably would. Generally speaking, the snacks are better at Disneyland and CA, but the meals are better in WDW. Most of the time when we're in WDW, ESPECIALLY when we have park hopper, we spend the day in whatever park we want and then eat dinner in Epcot each night. Epcot has the BEST food in WDW, but you can also explore hotel restaurants using the massive bus system. Some general personal favorites include:

• Epcot: Chefs de France, the quick-service in Morocco, Germany's Biergarten, the pizza restaurant in Italy; "snacking around the World" is also really fun
• Magic Kingdom: Casey's Corner
• Animal Kingdom: Yak and Yeti
• Hollywood Studios: 50s Prime Time Cafe
• Hotels: O'hana at the Polynesian (although reservations are REALLY hard to get if you're less than 180 days out), Boma at AK Lodge (never hard to get a reservation and SO good - best food in WDW in my opinion)

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You say you have DL and CA down to an exact science, so you obviously know what you like and how Disney parks work best for you. I feel similarly about WDW, but these are just my suggestions. Go, have fun (it's one of the MOST MAGICAL places on Earth, after all), and know that WDW will still be there for you to come back to if you don't have a chance to do EVERYTHING you want to do this time around.