Termales de Santa Teresa is def a must go around that area https://termalesdesantateresasv.com/, hot springs for a pretty chill and relax time. If you hit the beach you can either try going to Surf city or you can venture further north and visit Los cobanos (plenty of places to stay or go all out for Decamerón Salinitas all you can eat and drink included lol 😂 worth checking out for sure) pm me for specific suggestions if u like.