St Lucia has always been a troubled spot, with Castries area a no no for tourists even today. I dont know why anyone would ever go to Rodney Bay, its worse than Charlotte Amalie or Phillipsburg in terms of crowds, taxis, overbuilt, gettos, etc. It's ugly as well.
I have been to St. Lucia most recently in Sept/Oct on my way from Dominica to Grenada and back. Here are the places I think you can feel safe and have access to the nice inland sites there:
Marigot, for customs, then go south to Anse Cochon or my fav Les Canaries, where you can walk to some falls within 45 min. Soufriere for customs, but the immigration guy is hit or miss. If you don't do customs, just tell the SVD customs, in Chateaubelair or Bequia, and they won't cause a problem with you.
The Pitons are one of the great anchorages/mooring fields in the entire Caribbean and are not to be missed. The boat boys there were quite pleasant and helpful and not expensive. snorkeling is world class and i always am followed by a pod of dolphins when i head south...its pure magic. And you can climb either Piton of course!

There was a boarding in Tobago Cays last year and Union Island has its share of issues, but dont overnite in Clifton, go to Chatham and eat at Sun Beach Eat, tell Vannessa and Secki I sent you, i set up their ring toss game.
Bequia has had more problems than anywhere else, but is a nice place to visit nonetheless. Mayreau is my fav for its quirky bars--Last Bar Before the Jungle, Robert Righteous and de Youth, Dennis' Hideaway--and amazing setting at Salt Whistle Bay. Canouan is a waste unless you want to play golf, and Mustique is nice if you want to spend some $$$.

I found Martinique to be ok, but nothing special, Chaudiere has nice snorkeling, St. Anne is a cute town, but the people are more like Paris French, not Caribbean French like you find in Guadeloupe. A visit to Diamond Rock is a trip!

Hope this helps all of you, contact me if you need more help, i live in Dominica on my IS 37 Sanctuary and sail up and down the islands all year, eg I will be going up to St. Barths for the Bucket Regatta in late March/April.

Peace.