Hi Flyfishing42 - welcome to our online community.
2-4 hourse puts you well into central PA. If you're mainly interested in trout fishing (April is prime time for trout fishing), I'd spend those three days in center state. There are many streams in the area, many well known such as Spring Creek or the Little Juniata. However, these streams, although popular, can be tough for beginners. I'd suggest focusing on some streams that are stocked with trout, such as Bald Eagle Creek. The northcentral PA counties such as Potter, Tioga, or Lycoming are very good in April too, although this might be stretching four hours, but probably not by much.
If you hit the "Where to Fly Fish" link on the upper right side of this page, you can search trout streams by county and region.
Good luck with your trip plans!