Hey man. I grew up riding in Harrisburg. By far, the best, most convenient location to ride is on the Susquehanna river above the York Haven Dam. (Basically, right beside Three Mile Island.) There is a free ramp on the Goldsboro side, and a private ramp (the Tri County Marina Boat Club, 15 bucks to launch) on the Middletown side. My dad's been a member at the club forever. It's a couple hundred bucks a year, and then you can launch for "free" all season and have preferred parking, if it's something you'd be interested in.
Now, if you ask around, you may hear that boating at the York Haven Dam is risky because it's too shallow and there are rocks. Don't be scared away. True, it is shallow in places, and there are rocks in places, but if you know where to run (and it's really not that hard to master) and avoid running when the river is low (say, below 4 feet as measured at Harrisburg) you will be fine. My dad's mastercraft has 2000 hours on it, and about 1600 of them were run at the York Haven Dam.
With respect to wakeboarding, the water is really, really, really good. During the week, it's glass all day long. During the weekend, it's glass all morning, most evenings, and is usually rideable all day. The riding conditions at places like Raystown and Blue Marsh don't come close. Both are beautiful lakes, but Raystown is garbage by 10 am, and Blue Marsh, because of its shape, is waked out by just a handful of boats.
If you end up with a boat in Harrisburg, I'd be happy to show you where to run. I live in Philly now, but I come back to ride with my dad and high school friends about 10 times a year. Good luck!