Teresa and I did a lot of Assateague bike exploring last year. I loved it. Unfortunately I have to concur with Dave- that road south to Chincoteague seems to be only sand. Maybe there's asphalt under there, but I didn't see any black at all when I was there. HOWEVER, if I was down there with you (and I wish I was) and riding 34mm tires then I'd go for it. Knock almost all the air out of your tires. (be sure to bring the frame pump for the return) You're certainly not gonna pinch flat and you'll get much more control that way. As long as you can stay straight and maintain some forward momentum, then you'll be exploring more than I did. Have tons o' fun and tell the horseshoe crabs we say hello.