Park at the Salt Pond Visitors Center in Eastham on Route 6. Then cross Route 6 and take that road to the Trail, which is a short jaunt. Turn right onto the Trail. This stretch of the Cape Cod Rail Trail does not have many great views until you reach Marconi Station. The trail is basically flat and heavily wooded.
You’ll reach the Marconi Beach road and taking a right will bring you to the Station. The exhibit there is interesting and informative. The views of the Atlantic and beach are fantastic from the two viewing platforms. There are ample bike racks to lock up your bikes to enjoy some time on the beach if you desire.
Then it is back on the Trail to return to Salt Pond. Your entire trek will be about 12 miles.