First try some capsize tests under controlled conditions. Then after you add flotation bags-beach rollers you can think about it again.

Having spent a few years out in the middle of ChesBay and having used my NE Dory here on a medium lake I would be very cautious about crosiing the Bay. At this time of year things can get hairy very quickly and the rest of the year the water temps are dangerously low if you get swamped.  If you are looking for new sailing ground you might be better off heading North or South along your side of the bay to other rivers/inlets without getting too far from shore. 

I've sailed my NE Dory across the Albemarle Sound in NC, 28mi, 8hr round trip w/ 6-10kt winds. As well as some time around Deltaville, Va, swells are the concern on open water like that. I found that if the swells were big enough they dictated my sailing direction as much as the wind. And its tiring to sail for that long, your hands and back better be able to hold up to that long a trip. 

It would be VERY weather dependent, I would have to be really confident of the forcast to try a trip that long. Extra floatation, proper safety gear, and having everything tied down would give some peace of mind. But if you are comfortable sailing your boat, and its the right day, go for it. 

   I've never sailed one but if it's something you want to do just to say you did it I'd take all precautions pick a good day and enlist a support boat with capable rescue crew.

if you make it without help You did it! If not and you need to be rescued at least you're still alive to try again. 
 

Good luck PP