To counter a weekend’s worth of calories, make the hour trek to the 28,000-acre Caribbean National Forest—a.k.a. El Yunque —about 25 miles east of San Juan. Its dozens of trails are easily marked, clearly graded for difficulty, and lead to waterfalls, observation towers, and swimming holes. Your hotel can arrange guided tours, but the park is easy to navigate solo with maps and itineraries provided by El Portal Tropical Forest Information Center (787-888-1810) at the park's entrance.
Arrive early to beat the heat and the crowds and stick around for lunch at Las Vegas (Road 191, Kilometer 1.3, Rio Grande; 787-887-2526), the colorful, flower-filled—if oddly named—restaurant set right in the jungle. Order expertly prepared mod-Rican dishes such as skewered fish with hunks of bacon, a meaty osso buco, and roast pork with mofongo, another local garlicky, fried-plantain favorite.