Given the tide range on the coast of Maine and the sometimes challenging bottom, you would definitely be wise to up your anchoring game.  Two anchors would be prudent.  The Danforth type are OK in sand and mud, not so good in rocks, and pretty much useless in grass; plus, these cannot be relied upon to reset unattended in a shift of wind or tide.  A "Bahamian moor" with one upstream and one down will work in a tideway, however, given appropriate bottom.  I've used the Bruce-type claws with fair success, but even those can be tricky to set in rocks or heavy grass.  At least those will generally reset themselves unattended on a tide or wind shift.

I'd have a couple hundred feet for each anchor if you are going to be anchoring anywhere but near the shore in shallow coves with gently shelving bottom.  You'll often need 5:1 scope or more, which must be calculated at the expected height of the tide.  With a light, low boat like your Chester Yawl with no sail rig to catch the wind, and not much underbody to catch the current, you might get by with 5/16" line okay vs. the 3/8" recommended in that document.  Remember, though, the smaller the line, the harder it is to grip, and the more critical it becomes to have adequate chaffing gear at any point where the line bears agaist the rail, fairlead, etc.  It's amazing how quickly nylon rope with get chewed up if things get bouncy.

A real compass is a good idea (GPS can fail), as are waterproof charts, parallel rules, and divider and the knowledge to use them should the electronics become unhappy with the salty environment.  A reliable timepiece, in conjunction with a slide rule (if you're not good at mental algebra) and a tennis ball on a string will allow you to do rough time-distance problems for dead reckoning if need be.  Horn, absolutely.  Bell, too, in case of need to anchor in a fog.

Maine...I am green with envy!  Y'all be careful out there....

.....Michael

Watertribe (the folks who do the Everglades Challenge and other long distance expedition races) have a required equipment list here.

Obviously that is for a 3-7 day camping & sailing expedition, not an afternoon out on the water, so adjust accordingly.  Most of the camping equipment you might not need.  My thought generally is, if I'm going to be out of sight when I capsize, its probably worthwhile to have most of the safety equipment on board stowed away someplace safe.  And, if there is any chance that I might be coming home from wherever in the dark, the night running equipment is worth it as well.

   Two other worthwhile sources of information are the Maine Island Trail Association Guidebook and outfitting videos featured on the Offcenterharbor.com site.