We're planning a small (12x20) timber-frame workshed based on trees available on our lot. We're located on an isolated island, and do not have access to a tractor to move the logs. The farthest log from the site would be about 200 feet away, through forest.

We're hoping to move the logs to the site with a block and tackle, and a log peavey once we're close.

Comments or suggestions, anyone? Does anyone have any experience with moving logs "by hand," without either draft horses or engines?

There is a product called an "ATV Arch" and also a "Jr Arch" used to move logs by atv and by hand. You can see both in action at Future Forestry Products web page. It is www.futureforestryprod.com These are a scaled down version of what the old timers called a log arch. The small one looks nice and is reasonably prices the "atv arch" cost more but will haul more. Just remember you can sell them after your done with this project if you don't need them anymore. Or you can have your welder make one for you.
Good luck on your project. Jim