Two nights would be optimal to explore and enjoy the the twin parks of Xetulul and Xocomil . A few hours is enough time to explore the ruins of Takalik Abaj , but the excellent accommodations at Takalik Maya Lodge  might keep you busy for another two days.
From here or nearby Retalhuleu , you can explore the Manchón Guamuchal Wetland Preserve  for some bird-watching or just unwind at its beautiful beaches. Retalhuleu also makes an excellent base for exploring some of the surrounding countryside by bike, thanks to the presence of an excellent outfitter based here.
If you are in search of sand and sun, you might find yourself spending several nights at Monterrico . If your interest lies in surfing, you’ll certainly want to spend a few days in Sipacate  or Iztapa . For sailfishing, Iztapa is the place to go and you’ll probably spend at least three days here.
The 25-kilometers along the Iztapa–Monterrico Road  is shaping up to be the closest thing to a Guatemalan Riviera and will certainly undergo some drastic changes in the next few years. For now, it’s still a sleepy seaside area largely dedicated to the production of loofah.
East toward El Salvador is another small seaside town, Las Lisas , with a couple of noteworthy accommodations.
The northernmost and quieter of the two border crossings is found at El Carmen, where a bridge across the Río Suchiate connects it with Talismán, Mexico.
The more active (and preferable) border crossing is at Ciudad Tecún Umán, 39 kilometers south. A bridge links this city to its Mexican counterpart at Ciudad Hidalgo. There are frequent buses from here to points along the Pacific Coast Highway (CA-2) including Coatepeque, Retalhuleu, Mazatenango, and Escuintla. Buses also depart from here to Guatemala City and Quetzaltenango. You can connect to either of the latter two via Retalhuleu, a better place to linger if a bus is not immediately available.
Both borders are open 24 hours, but you should try to be out of border areas by dark. As elsewhere in Central America, border areas here are rife with crime thanks to immigrants trying to make their way northward and those who prey on them. There are some basic hotels and restaurants here.