Meg, I stayed at Little Dix Bay in Virgin Gorda, but it's very, very expensive, but I do have some info. I went a few years ago, so I don't remember car rental prices, but I don't remember anything costing outrageous prices.
If you can access the beach at Little Dix Bay, I'm not sure if you can drive in or park outside and walk in, the beach has excellent snorkeling. The food prices are very high, so don't count it in as a place to eat. I had a meal plan there, so I didn't eat anywhere else that I can recommend.
Little Dix Bay offered free boat shuttles to coves where you couldn't reach by foot or car, but all the bays I went to were calm. I think the only thing that would churn them up is if there was a storm. I found the water everywhere to be very calm and also at The Baths. The Baths is a beach with huge round boulders on it. The boulders are the attraction, but otherwise, it's just another nice beach.
I forget if it's Bitter End Yacht Club Resort that's at the end of the island, but a resort at the end of the island has small boat rentals, like Boston Whalers with small engines. You actually would have to sit in front to keep the front down, but it's great. The prices for the boat were reasonable at that time, so they may still be and if they are, take one out. It's a must. You can motor that baby to a small unihabited island for snorkeling and perhaps some naked swimming if you wanted privacy on empty beaches. Also, off the shore of the Bitter End Yacht Club is a place called Saba Rock. It's this rock that's has a bar on it. It's fantastic. You can dock your dinghy (Boston Whaler) there and order a great tropical drink and enjoy it on their outside seating. You can see all the small fish hiding under the short dock of the bar. I watched a pelican land on my motor and hang out. I was so much fun. I don't know if there is any place like it.
You'll have the huge yacht people waving to you as they realize you can't afford their yacht, but still are out there boating and enjoying the same pleasures as them. The boat just has a motor that you adjust to turn, no steering wheel, but it's easy to use, just use caution when going to another island to avoid the rocks that may be close to shore. You can easily drag the boat on shore to snorkel, and perhaps bring lunch with you.
If I can answer any questions, e-mail me at
lipstickhiker@yahoo.com. I love Virgin Gorda. It's my favorite place, because it's quiet and the water is calm. I don't swim, but with snorkel gear, I can be bouyant because one or two pushes with the flippers will keep you afloat, so please try it. You won't drown. The snorkeling is great there. It would be a shame to not try it or do it in a not as good place and realize you missed a great opportunity when you were at Virgin Gorda. You can even go vertical and stay afloat with a few paddles of the fins. Take it from a non swimmer and try it.