Altar Rock - Moorish Delight Trail is a 2.4 mile out and back trail located near Siasconset, MA and is rated as moderate. The trail is primarily used for hiking and is accessible year-round.
This trail actually runs along an old jeep road. The trip to Alter Rock is hilly but pretty easy. Alter Rock used to be known as the highest point of the island but apparently they were mistaken and now That is Folger Hill which is in the vicinity.
As you get closer to Alter Rock you'll notice a radar array building. At the "peak" of Alter Rock there is a geodetic disk. The trails aren't marked at all so I didn't try Folger Hill...but did go to Gibbs Pond about a half mile away.
You can choose to back track to the parking lot or try other routes as there are many old jeep paths to take.