I have played 15 or so of his courses. My favorites are as follows:
Tioga Downs, NY (great terrain, great views, very good routing - now owned by local casino)
Columbia G & CC, NY (only did 9 holes here, original 9 in 1919, has a little plaque / memorial on the course, great terrain / routing, private that used to allow public play at off peak times of season)
Luray Caverns, VA (hidden gem IMO, in blue ridge mountains, amazing views, very good routing / use of hilly land)
Stony Ford, NY (played more than 20 years ago, but remember the course as a solid I-84)
Maple Grove (FKA Norwood), IN (well routed course on hilly terrain, back 9 has housing, elevated greens)
I would say most of these are in the 4 to 5 Doak rating maybe higher.
Chris