It seems , by map , all routes go thru bruges. Plan to drive aachen to bruges. Visit am and move onto Ypres. How is the traffic and how realistic to do the plan? Suggestions????
As a practical matter, it will take 3 to 4 hours to get to Bruges, where a car is a big problem. A car is useful for Ypres. Maybe train to Bruges?
It will take a whole lot of driving in one day and as Antwerp and Brussels are notorious for traffic jams it will be hard to predict how much time rests for you visiting Bruges and Ypres. It makes also a difference having the car already or not. For visiting both staying a night in one of the two places will make the trip more doable, rush free to my opinion. If using a car, in Bruges you can park next to the train station, costs (€0,70h - €3,50/24h). If no event is going on there is always a place free. Parking in the historic centre is too expensive and navigating a real challenge.
Like Tim notices taking the train is worth considering. With the Thalys or ICE via Brussels will take 2½hours and Bruges is a pick up point for guided battlefield daytours to Ypres.