Ronnie,
That will be a great time to visit. Expect cool (or cold if you're coming from a warm climate) nights, crowds during the weekend days, very few if any mosquitos and afternoon thunderstorms. Even on MD weekend it will be easy to escape the crowds. Head out early, take a ride on almost any marked FS road and see where it takes you. If you're bringing a dog, CSP requires them on a leash. Don't let them chase wildlife! Hit the Wildlife loop one morning right at sunrise and do the Needles Highway another morning. Here's a teaser for you from last weekend less than 5 miles from the park.
[youtube]http://youtu.be/p56B-kTcwyA[/youtube]
http://youtu.be/p56B-kTcwyAMore later.
Bob
(Hmm ... It's not letting me direct link a YouTube video. You'll have to click to follow it.)