Seeking 50th birthday destination

Turning the big 5-0 this December and trying to decide where to go. Have a Delta companion ticket, good for flights to Caribbean. Would like to go somewhere new – have visited Bahamas, Grand Cayman, Turks, and St. John/St. Thomas. We enjoy hiking, the beaches, rum, and good food. While we would be considering 10 days and willing to rent a car, would like to keep the lodging under $3k (no luxury AIs). Would love to hear your suggestions, and thank you. (Have been looking at Sint Maarten/Saint Martin, St. Lucia, and Grenada, open to anything. Delta doesn’t fly to Dominca.)