I agree with Dreammaker that if you've never done it and have the time...the ICW
trip is a wonderful way to go and to really enjoy it and see all the towns along the way properly you should allow a month.
On the other hand, if you need to be quick about it...then heading to Beaufort and jumping outside for 2-3 day coastal runs makes sense heading south at this time of year when you want to be able to duck back inside before bad weather
Coming back in the spring with the stream and prevailing winds, it is easier to just head
straight to Beaufort .
An invaluable guide if you are going coastal is Dodge's Guide to SE US Inlets which includes waypoints excellent charts
and pictures of all the navigable inlets south of Norfolk.