- Favorite CS in DCA: Smokejumpers Grill (located next to Soarin'). The chili burger is the best burger you'll get in the parks. Upgrade to the onion rings instead of french fries - you won't be sorry! Another recommendation would be Cove Bar since everyone loves their lobster nachos although personally I haven't tried them (yet). If you go, check out their secret drink menu ahead of time for something fun.
- Favorite CS in DL: Rancho del Zocalo (located in Frontierland next to Big Thunder Mountain). Their breakfast is actually pretty freaking great, I recommend the chilaquiles as they are very tasty and it's a healthy portion. I also enjoy this place for lunch/dinner - can't go wrong with a taco salad or enchiladas/asada plate!
If you're also interested in TS, I recommend Blue Bayou restaurant (make sure to make a reservation in advance!) which is in New Orleans Square. The dining area is inside the POTC ride and the ambiance is wonderful, as is the food! For TS at DCA I recommend Carthay Circle and make sure to get the biscuits.
Typically everyone's must-do rides are the mountains (including Matterhorn) and Indiana Jones. Since you're a WDW vet you should definitely check out our Small World which (no offense) totally beats the WDW version.
In DCA, Cars Land is a must for sure. It's impressive on its own but even moreso if you've actually seen the movie beforehand so I recommend watching before your trip if you haven't already. Get your first FP for Radiator Springs Racers as those go pretty fast. Soarin' is the same as WDW so I wouldn't say it's a priority at all. Definitely ride a swinging gondola on Mickey's Fun Wheel and don't write off Goofy's Sky School - it's actually a *really* fun roller coaster even though it's aimed at children.
One fun little tip for you is to check out the bridge at Pacific Wharf. You won't feel anything just walking across the bridge but if you stop and stand on the bridge you'll feel it shaking because it simulates a 2.0 magnitude earthquake.
Have fun!