Getting there & away
You can get to Patan from Kathmandu by bicycle, taxi, bus or tempo. It's an uphill and choking 5km bike ride from Thamel to Patan's Durbar Sq. The trip costs around Rs 130 by taxi.
Safa (electric) tempos (Rs 7, route 14A) leave from Kantipath, near the Kathmandu main post office in Sundhara district, as soon as they are full. Double-check the destination when getting in, as some run to Mangal Bazar/Durbar Sq, others to Lagankhel bus station. When returning, a few tempos branch right to Koteshwar instead of continuing to Kathmandu centre.
Local buses run frequently between Kathmandu's City (Ratna Park) bus station and Patan Dhoka (Rs 7).
An interesting route back to Kathmandu is to continue northeast from the Northern Stupa down to the interesting ghats of Sankhamul, across the footbridge over the Bagmati River and then up to the Arniko Hwy near the big convention centre, from where you can take a taxi or cycle back to Thamel.