Jungle yorick is terrible in my opinion, because none of his itemization issues are really helped by items you would normally pick up to jungle effectively.
He's not bad in lane though. Pretty much impossible to drive out of lane once his E gets going. Don't take manamune, learn to manage your mana instead of spamming like a noob. Philo stone + HoG early are the way to go, then grab boots3, Atma's, and see how the game is going. If you need to be tanky, grab warmogs for the giant health pool, force of nature or banshee's for your MR item if taking lots of AP damage, or thornmail if taking lots of AD. Then pick up a late game DPS item - frozen mallet or infinity edge or black cleaver, imho. Upgrade philo stone to elisa's miracle. Flash Ghost summoners. You are really hard to kill because of tankiness, your Q speed, your W slow, and your E lifesteal, and summoners. And you can chase because of all the same reasons.