I have played a few Ross courses, though most are not what would be considered his best or most pure courses. I still have not seen Pinehurst No. 2, Seminole, Holston Hills, etc. However, from the courses I have played, I feel like I have gotten a very good sense of what a Ross course really is. My recommendations:
Teugega, Rome, NY: By all accounts, this under-the-radar Ross layout is one of his best preserved courses. Sure, many of the old bunkers are now grassed over, but the skeletons are there in every case. The routing, bunker positioning, and greens are the same as when the course was built in 1923. The collection of Ross greens here is as good as you are likely to find, with many greens set into natural saddles or ridges. The club struggles with encroaching trees, and this course is a good display of how trees have compromised many of Ross's great layouts. However, the club has employed local archie Barry Jordan to restore some of the old bunkers and re-establish whispy fescues along several holes. If you want find out why Ross was great, Teugega is a good start.
Mountain Ridge, West Caldwell, NJ: We all loved the course when we played it at Muccifest, and it is certainly a classic. The focuses here are the routing (which brilliantly traverses a steep hillside), and the GREENS. Routing and greens were the biggest strengths of Ross architecture, and they are hard to beat at Mountain Ridge. The course is also a great example of Ron Prichard's restoration work.
The six Ross course of Rochester, NY: Oak Hill (East and West), CC of Rochester, Monroe, Irondequoit, Brook Lea. Each of these six are great for learning Ross. The East shows Ross the router, and it also shows how many of his courses have been compromised by trees, Trent Jones, and championships over the years. The West belongs in the Teugega/Mountain Ridge category, and it showcases an ideal Ross routing. CC of Rochester shows a once-gone Ross layout that Gil Hanse brought back to life. This was a course Ross re-did twice himself, and it includes an unusual set of Ross greens. Monroe is another Ross classic with tons of great holes on swooping sandy land. It also shows how re-done greens can detract from the character of a great layout. Irondequoit was built in two parts. The front nine shows early Ross working on outrageous land to create great golf. The back nine, constructed posthumously by JB McGovern, is Ross at his toughest. Brook Lea is a notch below the rest, but it still has the typical Ross flair to make it a great layout.
CC of Buffalo shows a different, more low-profile bunker style from Ross. It also showcases Ross's brilliant routing around a giant quarry.
The front nine at Thendara in Old Forge, NY demonstrates that Ross was a great designer of nine hole courses. The greens at this course are also some of his most outrageous. The 9th green in particular proves that Ross DID indeed build crowned greens outside of Pinehurst.
I've also played Kingswood and Orchards in New England, though neither course made a significant impression on me.
Of the courses listed here, my five would be:
1) Teugega--well-preserved Ross in Upstate NY
2) Mountain Ridge--great greens
3) Oak Hill (East)--routing, how Ross has been compromised
4) CC of Buffalo--the unique use of the quarry
5) Thendara--a nine hole Ross layout with great flair on the greens
Oak Hill West and Monroe are tremendous golf courses, but these five provide all the lessons about Ross that GCA buff needs to learn. The moral of the story is that Ross did not build a certain type of golf course, route a course one way, or have one definitive style of bunkering or greens. He built a great variety of courses that were natural, strategic and, above all, FUN. If anyone asks me who my favorite architect is, my answer is still DONALD ROSS.