Hi Lucy & welcome to the Forum!
Don't miss Brimstone Hill Fortress; Full Day Sail & Snorkel Excursion to Nevis; Full Island Tour (Thenford IS good, but most all of the drivers are as they are very proud of their island); any of the old Plantations (which will be included on your island tour); the liquor store within the Marriott that will allow you to sample all of the Brinley's Rum flavors;. Lastly and most importantly, remember the pace of life on St. Kitts is much slower than the pace you are accustomed to in N.H. Please be patient, try not to get upset and ENJOY YOURSELVES!
