I was there earlier this year.
Beaches are public however you have to pay for chairs, and in most cases pay for umbrellas, unless you bring your own. Rates and service vary. If you're going to be in the water the whole time you will not need. Some airbnb and similar hosts will provide chairs, cooler, and umbrella that you can haul as part of the rental, which can save you money.
You may want a snorkeling vest, for visibility, and in case you get caught out by the wind and surge. I wore one at least some of the time.
I rented a small car. Rates were reasonable. I would not recommend a scooter due to the consistently heavy traffic, absence of a scooter culture among the locals, and poor pavement conditions. If I were going to be on two wheels I would want the control, wheel size, and power of an on/offroad motorcycle although I didn't see these either. Also you will want to be able to haul groceries and beach gear. We did not have to pay for parking and only had trouble finding a spot in the resort area where you're staying, so if you have parking reserved there, bob's your uncle.
Groceries, go to Superfood plaza, north of where you're staying.
You are staying in the resort district near the NW end of the island. We did not find any good snorkeling in that immediate area however we had a good day at the beach at Surfside Beach where we stayed at Reflexions restaurant. Beach here is sandy so not much to see. The restaurant provded beachside service including a loveseat with a sunshade, and had good food and reasonable rates.
If you drive north to Arashi Beach you can swim over to the reef area where the boat tours go (assuming you're relatively strong swimmers and have good fins). The beach here is rocky and not particularly good for swimming, but that means there is more to see. I would not characterize the snorkeling as fantastic but it was OK. We went early and scored a spot under a tree. There were various vendors for food and drink. We encountered a group of topless sunbathers here, so apparently that's permitted or at least tolerated.
The most interesting snorkeling was much farther south at Baby Beach and Mangel Halto beach.
Baby Beach is popular among families because there's a protected area that is uniformly shallow for, how shall we say, swimmers who are still learning. It is connected to the ocean through a series of channels and basins. If you can handle the surge and keep from crashing into the rocks, you can swim into these basins and there's some good snorkeling with quite a few reef fish. I had a great time swimming around in the surge and watching all the fish. There are kite surfers in the adjoining area, who are fun to watch. Prices for chairs and canopies were higher here due to there only being one vendor on site. There's a restaurant called La Granja on the way back that we enjoyed, inexpensive latin-caribbean fusion. There's also a fish market that's really good but kind of expensive, very casual, order at a window and they prepare the food and bring it to your table. Ask around for name and directions if interested
We really enjoyed Mangel Halto beach. Snorkeling not as good as the pools at Baby Beach but much easier. I was able to bring my wife who does not swim well. Shallow, mangroves, rocks. The beach is secluded and mainly appeals to locals. There are some umbrellas and tables that are free, come early to score them and bring chairs. There are no bathrooms or services nearby but there's a local bar off the beach. Sand beach with tree cover, mangrove, and scrub made for some seclusion and protection from the sun and wind.
Hiking wise Arikok Park/Dos Playas is nice also in the southeastern part of the island. There is an admission charge. There are some caves in the area that are open limited hours but fun to walk through.
Dutch Pancake House near where you're staying is good for breakfast or lunch and reasonably priced for the resort area. We ate there several times.
