We are going in March, but probably won't book rooms until about November. Can I still book meals without having an actual room reservation yet? We are also going to be doing DDP this trip as this is what my dh wants to do. Personally, I wouldn't, but he wants to try.
Yes, you can book ADRs 180 days out regardless of where you are staying. Don't forget -- offsite people eat in WDW restaurants too. Your booking has nothing to do with how you are paying for the meal.