Pros:
36 baskets and 54 tees. Blue and white share baskets but use different approaches, while red is a completely separate course. Red leans more strongly toward technical, wooded holes.
There's a good variety of holes. Most of the course is wooded, some of the holes heavily, but there's also a decent number of wide open shots to be made.
While some of the signs are showing some age, navigation is pretty easy, with a sign near most baskets showing the direction to the next tee.
Benches, benches everywhere. Each tee has at least one, sometimes three or four benches. I try to play early, so I haven't seen how bad the crowds can get.
There's two practice baskets by the parking area for warmups, along with a couple of picnic tables and more benches. Someone around here clearly likes benches.
Cons:
I've been working on the island for several months. I loved the course in the winter, but now it's summer and the grassy areas are getting knee-high and taller, while the wooded rough is getting very thick with many pockets of poison ivy.
Tee pads are a mixed bag. Many are bare dirt, some are gravel, some are rubber mats, and some are astroturf. There's been a couple of upgrades recently, but nothing as permanent as concrete anywhere.
I can't find a course map anywhere online. There's one on the kiosk at the course, but it's old and doesn't include the red holes.
Other Thoughts:
If you're in town for vacation or work without your bag, The Lazy Frog in Oak Bluffs has a great selection of discs. The gas station just south of the course also has a dozen or so for sale if you're desperate.
A couple of holes have strange OB markings running across them that make absolutely no sense. A local might understand them, but I had to just ignore them.
Despite the name "Riverhead" and the location on an island, there's no water of any kind to be seen.