We have been to Cedar Key by sailboat several times, most recently last summer. We draw 4.5 feet and have never had a problem with the main ship channel (south channel). At least 7 feet at low tide. The Northwest channel had a few shallow spots a couple years ago, about 5 feet. You can
anchor NW of Atsena Otie Key in 8 or 10 feet of
water. Coming in from the south, turn to the NE at "27" and proceed up next to the key just past the dock. There is a dock on Atsena Otie key and a short nature trail that goes through the ruins of a pencil factory and ends at an old cemetary. Last year the mosquitos ate us alive on the nature trail.
You can also
anchor off the waterfront, either to the NE or SW of the city dock. To get there you make an "S" turn starting at "27" where you turn to the SE, then turn back to the NE at "30". When we were there last summer, the city dock was being re-built. It did not look like anything you could tie up to. You can take the
dinghy around to the SW of the city dock under a small bridge to a basin and tie up to the floating dock.
Both anchorages are well protected from the NW, N, and S. The shoals offer some protection from everywhere else.
There are other nearby places which are great places to visit especially Kings Bay on the Crystal River. The Clairborne Young book is always good. Another excellent book for cruising the Big Bend are is Rick Rhodes Cruising Guide to the Big Bend.