Kamra's real value is as a base or stopping point for the surrounding Attock District, which has a number of genuinely worthwhile sites within easy reach.
Attock Fort — 20 km west — The Mughal fortification built by Emperor Akbar in 1581 at the Indus crossing is the obvious first choice. The exterior and the views of the river gorge are accessible; the interior is military-restricted. Allow an hour for the visit including the drive.
Hasan Abdal — 30 km east toward Islamabad — A small town with a cluster of significant religious sites: the Sikh shrine of Panja Sahib (one of the most important Gurdwaras in Pakistan), the Mughal garden Chashma Shah Jamal, and the Wali-e-Asr mosque. Hasan Abdal is a genuinely interesting stop and considerably more welcoming to visitors than Kamra itself.
Taxila — 45 km east — One of the most important archaeological sites in South Asia, Taxila was a major Buddhist centre and Gandharan city from around the 5th century BC through the 6th century AD. The site contains multiple ruins spread across a wide area, plus a good museum with Gandharan sculpture. A full day is warranted if you have any interest in ancient history.
Islamabad and Rawalpindi — 70 km east — The twin cities are a straightforward drive down the GT Road. Rawalpindi's bazaars, particularly Raja Bazaar, are worth a browse; Islamabad has better restaurants and the Faisal Mosque.
Peshawar — 50 km west — The old city of Peshawar, with its Mughal-era bazaars, Qissa Khwani (Storytellers' Bazaar), and the Peshawar Museum, makes for a rewarding day trip in the opposite direction.