At Harrisburg, stay in the right lane after crossing the Pennsylvania Turnpike (I-76), and make a sharp right turn (exit ramp) to merge onto the bridge crossing the Susquehanna River. After passing through downtown Harrisburg, I-83 swings out to the east side of town. I-83 then exits from the left lane and heads north, at which point it joins US 322 West. At the NE corner of Harrisburg, 322 exits from the left lane to briefly join I-81 South, then exits from the right lane after about 3 miles. Stay on US 322 the rest of the way to State College.

You will have interstate all the way to Harrisburg, then limited-access highway most of the way to State College, although there is a two lane section just north of Harrisburg that can be pretty slow during rush hour. This section is now under construction and can be major bottleneck. The entire trip should take about 4 hours from the DC area, or about 3 hours from Baltimore.