Taxis are costly, as on most islands. We opted to rent a car because we like the freedom that it affords--we can tour the island at our own pace, double back and see things again, scoot out to the grocery store to get snacks or booze, go out to dinner, explore a different beach every day--that sort of thing. If you think you're going to be mostly resort-bound, it might be more cost effective for you to hire a taxi each time you go out. I'm not sure about the St. Kitts bus service, as I never used it.

I recommend renting a car, driving is on the left but fairly easy. It would be really expensive to take a taxi from the S. Frigate Bay area to places like Brimstone Hill, Caribelle Batik (which are at least 45 minutes away), or the other direction such as touring the peninsula and seeing Turtle Beach etc (about 1/2 hour away). Even going downtown is probably at least $12 - 15. One idea would be to just rent a car for a few days. Where are you staying?

Bus service on St. Kitts (and Nevis) is really by a seriers of mini-vans that travel between various villages on the island. They do not run on "schedules" and you might have to take 2, 3 or even 4 different vans to reach a certain location. For instance if you are in the Frigate Bay area and want to go to Brimstone Hill you might have to take a "bus" that goes to Basseterre, than a second one that goes as far as say "Boyds" where you get the bus that goes between Boyd to Old Road and finally another bus that goes from Old Road to one of the villages past the turnoff to Brimstone Hill. That trip could take you well over 90 minutes and you'd still have to hike up the hill (probably another 20 minute walk)from the main road to reach the entrance to the Fortress.

Really, tourists usually don't find the buses to be a viable means of travelling around the island.

Taxis will get expensive and two r/t's (including tip) a day to almost anywhere on the island in a cab will cost you more than a rental car.

Budget for a rental car, at least for part of your stay. You'll be glad you did.

I'm finding your advice helpful. We'll be staying at the Marriott on North Frigate Bay. We don't mind walking but if the south side of the island or a wine/grocery store is not within walking distance we may have to opt for a rental car. Don't like the thought of another $25 for the island license though.

There is a small convenience store and several restaurants within a few minutes walking distance of the Marriott. There are a number of 'beach bars" on South Frigate Bay, about a 15 minute walk "across the golf course" from the Marriott.

All of the other beaches (and their respective beach bars) on the southern pennisula as well as all other beach bars and restaurants around they island are much too far to walk. You will need some form of transportation. You should seriously consider getting a rental car for at least part or all of your stay on the island. Without one, you will either spend a great deal on taxi fares or miss out on most of what this island has to offer.