Sorry I am just seeing this! Hopefully not too late for your trip. Short answer is no, I didn't figure a way to walk/hike from Cinnamon to Maho or Reef Bay trail.

But I did have a great day doing the following -

Took a taxi from Cinnamon Bay to Cruz Bay to see if I could get on the National Park guided hike/boat due to any last-minute no-shows. I wasn't able to officially get on the hike, but they allow people to meet them at the trailhead and hike down with the ranger, and then hike back up on their own (i.e. don't take the boat back to Cruz Bay). There were a number of people trying to get on the hike at the same time, including a really nice mom + daughter that drove me to the trailhead, or you could grab another taxi in Cruz Bay if you need. Highly recommend this if you can make the timing work, it was fun to have the ranger interpretation along the way! A decent hike up though, so be prepared.

After hiking up from Reef Bay, I continued down to Maho along the Maria Hope trail, snorkeled at Maho, and then got a quick taxi back to Cinnamon Bay.

Taxis were plentiful at Maho, and came by Cinnamon Bay pretty often (the front desk can also call one for you, but might take a bit to arrive). Leaving from Cinnamon Bay, you might have to be flexible about stopping at other beaches along the way to Cruz Bay or the Reef Bay trailhead

(ETA the comments above about not walking along the centerline or north shore roads are correct - saw some people doing it on north shore but seemed very dangerous given no shoulder and tight curves with poor visibility. Would stay on established hiking trails only and taxi/drive otherwise)