The reason for the odd wrap around cockpit in the B-66 is because it was adapted from the Navy A3D/A-3 series which had two seats in the traditional pilot/co-pilot side by side arrangemt.The A3D was designed from the start as a single pilot airplane,though,and the right seat was for a Navigator/Bombardier.There was also a third aft facing position for the plane captain/rear gunner.
None of these positions was fitted with an ejection seat.The Navy black humor types said that the designaion A3D meant "All Three Dead".Ed Heinemann,the designer,went with a roof hatch for ditching and a bail-out slide in the lower entrance door in lieu of ejection seats.This was mostly a weight saving decision,but also because the early ejection seats had some severe operating limitations.
When the USAF ordered the B-66 based on the A3D,they insisted on ejection seats.There wasn't really room for two ejection seats in the cockpit area.For a look at the A-3 arrangement,this phot shows the Nav's instruments in the right side of the panel:
http://uscockpits.com/Later%20Attack/ER ... arrior.JPG