We have visited that park by water a
lot of times, albeit not since the pandemic. Showers are nice, and either have your Washington Parks pass or be prepared to pay their standard nightly rate. I understand that the dock power is working nowadays. And yes, do plan the hike to the top of the Rock. Awesome view.
Enroute, stay in the channel. Once you get much above Camas, most of what you might hit is less and less likely to be sand, but rather hard rock. It is well buoyed, and do pay attention to your charting. The marked channel moves you over closer to I-84, and even tho the water looks fine a long ways north towards the Washington shore, the bottom is only a few feet beneath it. There is barge traffic, but if you hail the skipper and exchange pleasantries, he will advise you where he is heading so you can avoid him.
Entry to the inlet for the Park seems to puzzle some boaters... take it slow, and stay in the middle to avoid the gravel bars that build up on both sides. Some folks anchor out, but be aware that the bottom is populated with small round rocks and anchors can find it difficult to really bite. There is a gentle current down thru the park dock area from some river flow that diverts around the north side of the little island. That current keeps the water clean for swimming, tho.
The docks (and park) can get busy, but unless you are there on the Labor Day weekend, you should find room. On that particular weekend we have rafted out as far as six deep when our sailing club visited.
Mind the fishing folks out in the channel if there is a season for salmon. You do not want to snag a line or an anchor line.
As you might suspect, the Gorge scenery is amazing!