Although mountainous, Guatemala's highlands are not the Andes, so driving isn't too treacherous, and primary and most secondary roads are in decent shape. The Pan-American Highway (CA-1) heads northwest out of Guatemala City, where it is called the Calzada Roosevelt. It bypasses Antigua and passes through Chimaltenango before reaching the highlands. The highway, being expanded to four lanes in many sectors, forms the transportation spine of this region, although most of what you'll want to see lies off the highway. (The northern hub city of Huehuetenango and the market town of Salcajá are the only two sights we list that actually sit on the highway.) North of Huehuetenango and Nebaj, roads deteriorate to dirt or gravel.
There is only one national car-rental agency in the western highlands, Tabarini. It might be easier to rent a car in Guatemala City instead.
Tabarini. 9 Calle 9–21, Zona 1, Quetzaltenango, Quetzaltenango. 7763–0418.