Route 3
To Avenida del Sol
Route 3 takes you down the Avenida del Sol to the gardens below the Qorikancha. Walk uphill next to the Qorikancha, which I highly recommend visiting. Afterwards, walk up the pedestrian passageway past the Kusicancha archeological site.
A short left down Calle Maruri takes you past an office where you can buy Machu Picchu tickets. Turn right up pedestrian Calle Arequipa that leads to Plazoleta Santa Catalina. I also recommend visiting the Santa Catalina Monastery before walking the last block back to the Plaza de Armas. Except for a few steps from Calle Maruri to Calle Arequipa, this route is wheelchair accessible.