The armored US Humvees sweep through the pine-fringed village of Zuruk and boys and girls line the road, grinning with their thumbs up, shouting for pens and candy.
Just thirty minutes drive away, there are almost no smiles. Neighboring Naka district is Taliban country.
The last four times that US soldiers stationed at the Urgun base in the restive southeastern province of Paktika made the three-hour drive out here, they were attacked by homemade bombs and shot at.
This two-day patrol to Naka and Zuruk is part of a wider push by US troops to bolster the control of the Afghan government along the restive border with Pakistan as the country approaches key parliamentary elections next month.
As the 11-vehicle convoy winds along the dry riverbeds from the safety of the walled base, the contrast between the neighboring districts highlights how much progress has been made over the last year -- and how much work remains to be done.
In Zuruk the police chief, Mohammed Ayaz, feels safe enough not to carry a gun, while a girls school funded by the US military is going up a stone's throw from the police headquarters where a new squad car donated by the Americans sits in the shade of a fruit tree.
"We've had a lot of help from US forces with school supplies, and renovating our district government building and we hope for more help," Ayaz said, surrounded by relaxed US soldiers who had taken off their weapons and body armor while in the town's police headquarters.
Lieutenant Justin Freeland said Zuruk just needs better communications and some new police checkpoints and then local forces will be able to manage their own security without much outside help from US troops.
"We are trying to get the local government here to function so that they will be self-reliant when we leave," he explained.
With fewer than 20,000 US-led coalition troops in Afghanistan, US forces are not numerous enough to enforce law and order but have to rely on building up the capacity of the Afghan army and the local police.
The effort has been patchy, with remarkable success in some areas and intransigence in others.
In Naka district, which lies 30km from the Pakistan border, poor security has stalled reconstruction altogether and hobbled the district administration.
The doors are hanging off the police headquarters and US troops are too busy planning to ambush Taliban militants and searching for homemade bombs to build schools or clinics.
The police chief, Jon Baz, is a former Taliban commander who joined a government amnesty program earlier this year. But with the numerous attacks on American troops in the area, the US forces say it's unclear which side Baz is actually gunning for.
"In Naka, we built police checkpoints and they burnt them down so they didn't have to man them," 29-year-old Captain Joseph Geraci, leader of the 55-man mission to the two districts, said.
Afghan and US officials said militants have been crossing back and forth staging armed raids and planting crude homemade bombs along the routes used by US troops.
As the patrol draws to a close en route back to Urgun, Geraci's men set ambushes and lie in wait for the militants who attacked them on their last trip to Naka.
The convoy of Humvees stops on a road through a wooded valley and troops pick up a man in an area where intelligence indicated militants were lying in wait.