Does anyone have experience with independent excursions in San Juan?

Yes, the ships dock right at the bottom of Old San Juan. You can walk around the old town on your own & take the tourist trolley to get around. We also took the ferry over to the Bacardi distillery and rum tasting. You will need to get in a van when you get across the harbor. Others on the ferry will be doing the same thing.

Yes. We walked off the ship and guys were running around trying to get extra passengers to fill up their tour buses. We checked put their bus first and then gone on- the cost was half of what Carnival was charging for the same tour. We got to view the Fort, stopped at various places like an eatery and plaza throughout old. San Juan . Our guide even passed a bottle of flavoured rum to test. We also stopped at some liquor/alcohol outlets for some free sampling as well. Quite the experience.

Yes, the ship docks right in the middle of the historic old town. So, walking around is very easy. We were last there in December and for the most part San Juan was up and running. There were still some signs of the hurricane but I am sure by now it has improved. In addition to walking around the historic area, you might want to explore the Paseo de la Princesa. It is essentially a walkway that goes along the old city walls (on the outside). You can walk from near where the ships dock to all the way around the fort. It offers some magnificent views but it is a lot of walking! More info here: https://sanjuanpuertorico.com/paseo-de-la-princesa-old-san-juan-puerto-rico/

Also, the ferry terminal is right next to where you dock and for about .50 cents you can buy a one way ticket that goes across the bay. Once you arrive that the other end, there are plenty of taxis and shuttles that will give you a lift to the Bacardi Factory for about $7. You then have the option of taking a tour ($15) or just poking around. We visited the Visitor Center for free and picked up some nice souvenirs and a bottle of rum! All of that for about $23 per person. A taxi from the ship will cost you twice the amount and an excursion brought from the cruise line will cost even more.

We went to San Juan on a cruise with Carnival in May and went back to visit the island this past weekend. While we were this this past weekend, we went to one of the Forts. Entrance is $7 per person if I remember correctly and is within walking distance of the port. Also, the port is right in Old San Juan so you can just walk right into town. The rain forest is always beautiful. Also, there are jet skis' at the Marina if you are into that as well. (It is located in the lower level of the Sizzler). There is a place called Raices Restaurant that is known for their stuffed mofongo which is really good that is right in Old San Juan as well. Sometimes there are local artists/vendors that have stands setup where you can purchase souvenirs right along the street near the port also. I found several things to do on TripAdvisor. We took a sunset sail through a company called Sail PR that I found on there. In order to make your departure time, you would probably have to take an earlier sail if you choose to do so. The Captain is named Francisco and he is very informative as he sails around the edge of the island telling you about the different points of interest.

Hope that helps!