I had never been to Roosevelt Island - in fact, I hadn't been to any of the smaller islands that compromise New York City. Roosevelt Island is the only little island around Manhattan that is actually inhabited*.
You can get there by subway or by tram, and there aren't many cars on the island. Of course I was excited to take the tram, my philosophy on trams being similar to my philosophy on fire towers.** The island is two miles long but probably only a quarter-mile wide. The tram lets you off near the southern end, so I decided to walk around it counterclockwise.
That meant I started by going through the Roosevelt Four Freedoms Park (at left). It is still being built but is not fully accessible, which is a problem because (a) the Roosevelt in question is FDR, the prez with a wheelchair, (b) Roosevelt Island has a significant disabled population and (c) construction began well after the ADA. The park so far is vaguely visually interesting, but as of yet there was no evidence of the four freedoms, just a giant FDR head.
As I started up the east side of the island, I was blocked by construction and had to retrace my steps, so I figured I might as well go clockwise.
Aside from a few historic buildings such a lighthouse and smallpox hospital, almost every building on the island dates from the late 70s or later. The look and feel is very 70s/80s. It's not necessarily aesthetically beautiful, but it took me some time to identify what I was feeling as a weird mix of nostalgia and admiration of the architectural consistency. Smartly, they kept the entire waterfront open, so it's possible to walk around the entire island.*** At the northern end is an old lighthouse; alas, it is closed.
Going down the eastern side of the island isn't quite as attractive. That's partially because the hospital and some public services have their backs to that side, so there are a lot of parking lots, that kind of thing. Also, the view of Brooklyn doesn't necessarily show Brooklyn's best side - the Costco looks as ugly as every other Costco. On the other hand, the power generating plant looks pretty good.
Eventually, I ran up against a gate at the edge of construction and returned to the tram.
All told it was a little over four miles, completely flat. Only parts of it were shaded, so bring plenty of water in summer, along with a warm jacket for windy days.
* There is a small population on Wards/Randall's Islands, but you can't just move there. There are various shelters and services on Wards Island, so I suspect the population consists of either users or employees of those services.
** "Never pass up an opportunity to climb a fire tower."
*** Excluding, obviously, the temporary blockage of construction.