The Baths is by far the main reason people visit Virgin Gorda. We've been to a reasonable number of Caribbean islands at this point and it's definitely one the most unique places we've seen.
Ultimately, the Baths is a couple of beaches and a giant pile of leftover volcanic boulders from long ago. The ocean water has done what water does and eroded them into a fantastic series of pools, grottos, caverns and tunnels.
There is a parking area for the Baths where you can purchase tickets. There are also showers, a snack bar, a restaurant and a handful of random souvenir vendors. From here the shortest trail option takes you directly to the beach in the first picture above. This is a perfectly nice beach with wonderful water but if you aren't going any further than this, you should've gone to Spring Bay which is quite similar -but free. The main attraction here is the trail to Devil's Bay. This is the alternate entrance to it. Don't worry, you don't actually have to be a small child to fit inside. There is a slightly larger entrance further down.
This room, perhaps the third or so you reach along the trail is called the Cathedral. It is a popular picture spot and if you Google it you'll find a few hundred pictures of supermodels and newlyweds standing hereabouts.
As you may have noticed by now, this may not be the best outing if you are claustrophobic. You can avoid most of the really tight openings by following the easiest path through. There are some rope-assisted inclines and a couple of steep ladders that need to be navigated.
Our five year-old son had no issues following this trail. The water (which is connected to the ocean, and thus somewhat tidal) was chest high on him at times but really the biggest danger for us was that he liked to squeeze through openings that there was no way we would fit through. Often, there were alternate routes to the same place and there are even some underwater connections if you're feeling adventurous.
Here's our piece of advice for visiting the Baths: Don't wear flip flops. You can probably navigate this barefoot although it may be painful depending on how hardy your feet are. We wore water sandals which were great for climbing over rocks and exploring. People wearing flip flops were generally struggling with some of the harder climbs.
A great thing about the Baths is you can play in the water here with no sunscreen because there is no direct sunlight. If you have children, this is a never-ending series of kid-sized pools (some are actually quite deep).
Most people visiting the Baths are day-trippers from assorted other Virgin Islands. We talked to people who took the ferry to Spanish Town and then one of Gorda's open-air taxi trucks to the Baths. We also talked to several people who arrived by sailboat or raft and were dropped off "off-shore" to swim into the beaches. From what we saw, this really wasn't a particularly long swim but it was a swim (and yet another reason not to wear flip flops).
Parallel to the Devil's Bay trail which winds through the boulder caves is the water front side of the boulders. If you're snorkeling this is where all the good stuff is. Accessing it from within the caves is challenging but it's an easy swim back along the shore from either beach.
This is Devil's Bay, the endpoint of the Devil's Bay trail. It's lovely clear water (like most of Gorda), you can see the drop-off boats in the distance and the island of Tortola out beyond that. There is decent but not great snorkeling here in the bay, mostly around those center rocks or out along the far side. It is a very nice beach although we could see it being rather crowded in-season.
There are fish around both beaches, all along the shoreline and even in many of the cave pools. They are mostly minnows - if you look closely here you'll see about two thousand of them - but we did see parrot fish, angel fish, snapper and the usual assortment of small tropical aquarium fish.
If you don't like the idea of the moderately rugged cave trail, you can hike directly to Devil's Bay from the parking lot. This trail is only slightly longer (about 1km / a half mile) and is mostly downhill on the way to the beach. There are a lot of cacti and a lot of reptiles along this trail. You can also connect to a third beach that we hear good things about (we were hungry and on our way to lunch so we skipped it).
This is the fruit of the barrel cacti that are found all over Virgin Gorda and the nearby islands. It looks like it might be fake or plastic or certainly painted an artificial color. We assure you it is none of those things, we saw quite a lot of them growing directly on the cactus plants. We are told these are edible as well but not necessarily tasty.