1900 Park Fare is at the Grand Floridian resort, and the Grand Floridian just happens to be a monorail resort, so either before or after dinner, you can simply walk up to the monorail station, which is on the second floor, just outside of the main lobby, and get on the resorts monorail from there.
How are you planning to get from OKW to Grand Floridian? If you drive, you can leave your car at the GF lot and ride the monorail all the way around, ending up back at GF.
If you need to take a bus, then you would take a bus from OKW to Magic Kingdom, then take the monorail from MK to GF for dinner. And after dinner, you take the monorail the rest of the way around, back to MK, where you can get a bus back to OKW.
Either way gives you a complete ride around the resorts monorail, which stops at each of the 3 monorail resorts (GF, Contemporary, and Polynesian), and at the Magic Kingdom gates, and at the Transportation and Ticket Center (TTC).
If you have extra time, you can also transfer to the Epcot monorail at TTC. The Epcot monorail will take you to Epcot and back again, with a total round-trip time of about 30-45 minutes. The Epcot monorail has the extra advantage of actually circling inside Epcot before it gets to the station, giving you and your family a wonderful view of the park itself without actually going in.