No matter how wonderful the city of Petropavlovsk-Kamchatsky is, it's still just a city. And if you want to see the main attractions of Kamchatka you should leave the urban area and go into the wild.
It takes 3 hours to get to Gorely Volcano from the city by car.
A normal paved road ends after the village of Termalny. The further 50 km stretching along the forest zone (the home of hungry bears) are in terrible condition. Still there are many tourists lounging about and risking their lives.