There are lots of routes with lols of coasters to get there, but you want to head for Ohio. (No I'm not from Ohio.) In a ring around Ohio is the world's greatest concentration of coasters. Either in Ohio or within about 100 miles of the border are PKI, Kennywood, Lakemont, SFWoA, CP, Holiday World, SFKK, and numerous smaller parks. You can also continue over into eastern Pennsylvania and New Jersey for even more coasters.