Cars are not allowed in Gruyeres, my guidebook says that is only between Easter and the 1st of November and every Sunday. Parking is very close and free with just a short walk up a flight of stairs, past a herd of cows jingling their cow bells, to get to the village.
We took the Bulle exit from the highway, the way to Gruyeres is well marked.
The village of Gruyeres is totally carfree and so you have to park your car outside if the medieval townwalls and walk at least 400 meters in order to get to the market-square of Gruyeres. The parking of your car is free of charge and you will find lots of different parking-areas while driving uphill. I was lucky to find a space on the parking on top of the hill with just a very short distance to walk.
Gruyeres is 5km south of Bulle, 55km NE from Lausanne, 38km N from Vevey, 40km N from Montreux, 122km from Geneve. 63km south of Bern.
We easily drove there from Lausanne through A12 highway, there were clear signs, not much traffic on Sunday morning. As we approached Gruyeres we could see it on the left (pic 1), after some minutes we passed the first parking lot but we skipped it and parked at the parking lot near the entrance (pic 2). You can easily walk inside the village, don’t forget its totally car-free there.
pic 5 is the map of Gruyeres I got from the Tourist info, it's part of the free guide they provide you.
By public transport
You can take train from Lausanne or other towns to Bulle and then use the light train to Gruyeres-Gare/Pringy(next to the famous local cheese factory). Then you can either walk 15’ uphill to the village (where you can find the castle, the museums, the restaurants) or use the local bus (pic 3), here’s the timetable from the trainstation:
a.m. 6:56 - 7:31 - 8:13 - 8:49 - 9:02 - 9:49 - 11:18
p.m. 12:02 - 12:49 - 1:02 - 2:02 - 3:02 - 4:02 - 5:02 - 6:02 - 6:49