The Vaison-la-Romaine Roman Ruins site called La Villasse are on the west side of the main parking lot, across from the Office de Tourisme.
This La Villasse area is more extensive than the those of the Puymin area behind the ticket office. The site is vast, open and relatively flat, and contains the ruins of a commercial street of boutiques, thermal baths, villas and evan a small Roman zoo.
As you stroll through the ensemble of ancient walls, pillars and the occasional statue, you have a backdrop of the Haute Ville castle to the south, Medieval village houses of Vaison-la-Romaine and the distant Mont Ventoux to the east, and the 12th century Notre-Dame-de-Nazareth cathedral to the west.
The small Roman zoo we mentioned is called the Maison aux animau sauvages (house of wild animals), which we liberally translated to zoo. It's located in the roofed structure in the lower-right corner of our photo.
The entrance to the La Villasse Roman site is down a short flight of stairs, where you insert your ticket (purchased earlier at the Puymin site entrance) into a slot for entry through a turnstile.
The audioguide obtained from the Museum at the Puymin site also works here at the La Villasse site, with audioguide reference numbers posted around the site.