As for WCUSA, I have no frame of reference cause we went on a Tuesday morning during the school week and had the park to ourselves.
In May, yes, the local schools here do not get out until mid-June. Now, this does not mean it will not be crowded though. You will want to avoid BGE on Fridays and Saturdays especially. Many schools have different things going on, which usually includes a trip to BGE for a long weekend. Sundays are typically not as crowded, even though some, but not as many, schools are there.
Now, for WCUSA. This one is going to be a bit different than BGE. WCUSA is usually not as crowded as BGE in the time frame you have given. However, there is one factor that can change that. If the temperatures are hot and humid, you will likely see the park very crowded. However, if it is more seasonable and less humid, you will likely not incur the larger crowds.
Here's a concluding overview. I would suggest going to BGE between Sunday and Thursday only. As for WCUSA, I would try to limit that to a weekday, if possible. This will likely give you the best opportunity to have fun and complete everything without the large size of the crowds.
I hope this helps. :)
I went to BGE during the first week of June last year when it was open everyday, and schools were still in session. During the week, BGE was busy but manageable, and the day we went to WCU (a Tuesday or Wednesday, I believe) it was empty. Beautiful and fun, but empty. We had a blast. I will also say the the busiest times for BGE were Friday night and Saturday. It was packed the whole time. Sunday afternoon/evening, it was not bad at all.
If you need more info, pull up some threads from last year about my trip. I had lots of questions for the experts on this site, and they came through with flying colors! I had an excellent vacation in the Williamsburg area.
Hope that helps.
