Unfortunately, getting to SKB is always going to be "crazy high." I'm also in the Balt/DC region, and we go to Nevis every other year. I budget $800/person, round trip, and am happy if I can use miles or get a better fare. Make sure you try all 3 area airports. Even though you note high fares to SXM, do consider using that as part of your routing, and connecting to SKB from SXM using a local carrier like WinAir -- there are more flight options from the US to St. Maarten than St. Kitts, and you might get lucky and find a fare sale. Also, for our last Nevis trip, some of our group flew to San Juan from BWI using Southwest and then got to St. Kitts using Seabourne.