Where to view animals at Hayden and Lamar Valleys?

Heading to Yellowstone for the first time next week. My son (13) told us he didn’t want anything for his bday or for Christmas this year. He only wanted to go to Yellowstone. He REALLY wants to see bear, wolves,….all the animals. I know people recommend Hayden and Lamar Valleys early in the morning. My question is, are there specific pull-offs, trails, or do people just pull over on the side of the road? Any suggestions are appreciated. Just want to do my best to ensure it’s amazing for him.