(And i know you were joking/exaggerating about the beach)
Don't find a beach, that will greatly hasten mental and physical decline. The key is to find a sweet spot where you neither overdo nor underdo it, but folks need to challenge themselves physically and mentally nearly every day to avoid falling apart.
We've talked a lot on these pages about obesity in Americans which is a huge issue (pun, sigh) but the American belief on retirement is another huge contributor to the "decade of slow death" I see too many patients and family members go through.