JBo, the location is the Washington's Crossing State Park on the Pennsy side of the river.....literally right on the river. The bridge at Washington's Crossing, NJ will drop you right into the park - that bridge intersects Rt. 29 as it runs up along the river.
If you ran 195 across the state, pick up 295/95 around Trenton, past Rt. 1, right on down to the river and Rt. 29 North. Go about, oh, maybe 2 or 3 miles and you're right at the bridge. Word Of Caution; the Washington's Crossing Bridge is so narrow it makes Twiggy look wide. They've banned SUV's on it, tho, so passage these days is better.
There are a bunch of ways you can come, all good, some much better, but it will be a fine day no matter which way you come.
(p.s. - the registration form is at the first post)