The Petén is rugged country, where major roads are few and far between and highways are all but nonexistent. But because there are only two airports—one in Guatemala City, the other in Flores—you're forced to do most of your travel by land. Many of the roads in El Petén are still unpaved, the exceptions being the road from Santa Elena–Flores to Tikal, the road from Río Dulce in the south to Santa Elena–Flores, and a few others.
Proximity to Las Verapaces and the Atlantic lowlands—it's four to five hours from either region—make the Petén a reasonable overland combination with either, and air links to Guatemala City simplify travel here from almost any other region of the country.
Tikal. Arguably the most impressive of all Mayan sites, and rivaling even Machu Picchu in Peru and Angkor Wat in Cambodia in its ancient splendor, Tikal is a must-see.
Tikal Environs. Set at the end of causeway in Lake Petén, the town of Flores is a charming and walkable small town, with almost a Mediterranean air. The village of El Remate, closer to Tikal and on the lake, is another pleasant base for exploring the region.
Other Mayan Sites in El Petén. The complexes of Yaxhá, Nakúm, Uaxactún, and El Zotz are scattered around Tikal. They're all close, but poor roads limit the number of visitors, especially during the rainy season. Farther removed, southwest of Flores, off the road to Cobá in Las Verapaces, are the town of Sayaxché and its nearby Ceibal ruins.