I did it ......
Tom, I have a 37c as well, which I bought in Miami and sailed it over to Naples. From Miami, It took 3 days, mostly due to there being a tropical depression giving us 30 knots on the nose mostly from the southwest. This also precluded us from taking Hawk's Channel on the outside of the keys. I took the inside route (we have the 4' shoal draft), and motored through the ICW until Islamorada/Upper Matacumbe area - there is one drawbridge at US 1 to go through. We left Islamorada at 10:00 AM and overnighted to Marco Island (we arrived at 5:00 AM in the dark, unfortunately). You have to follow some marks until about 5 miles (guesstimate) north of Lower Matacumbe, then it's a straight shot up to Marco. If you have the deeper draft version of the 37c, you may run into problems if you catch low tide in the wrong area, but otherwise it should be fine. Another note, however, is that there aren't too many marinas on the inside route. E-mail me if you need any more specific info, and I'll dig it out of my logs....Pete