3B - what you are looking at is the SID chart, and the 273 DVR is the Dover SID track off 08R.
A 'straight-in' is not abnormal, but also not common except at quiet traffic times, and you can assume that most of the s/in traffic will be at idle for the arrival, so pretty quiet. If there is a 'common' straight-in track I would hazard a guess it 'normally' joins the centreline at about 15 miles or even further out.