I went to an All Inclusive in Guanacaste, not sure if this is for you if you wanna be in town but I enjoyed it. It was two huge hotels in a gated area, had a little esplanade with a casino, club, bar, some shops etc. It was right on the beach and a 10 min walk along the beach to a pretty popular bar. Tons of things to do and see from the hotel, plenty of organized trips as well and the hotel had 7 restaurants you could choose from for food as well as 4-5 bars to hang out in.
https://www.riu.com/en/hotel/costa-r...rica/index.jsp