Intruder -
I think it is Pittsburg landing... It's the one at the confluence of the Tucannon and Snake. Sometimes we would put in at Lewiston and then fuel up at Pittsburg landing. Sometimes we would put in at Pittsburg and run up from there. The biggest problem we had was I had a range of about 70-80 miles. I had to strap on 5 gallon gas cans on the back of the jet ski to make it home sometimes...
One time my buddy and his girlfriend were riding my second jet ski and there is a good sized rapid down below Pittsburg landing. we were jumping the huge rapids and his girlfriend fell off the back of the jet ski...

I raced towards her through the rapid, grabbed her hand and hauled her to the shore. It was a real close call. I'm not sure if someone can make it alive down some of those rapids.
I'm not sure the names of the rapids. I'm not sure where the actual "Hells Canyon" area starts. I know I went up past the confluence of the Salmon at least 15 miles...? (about to where the road from White Bird comes down to the river) I went up the Salmon at least 20 miles from the confluence...? (I didn't ever make it as far as White Bird) Not sure if it was legal or if I needed a permit. (alcohol+youth=stupidity) It was 1996-2000 and I was in college at the time... I remember one time there was a forest fire up the Snake and they were fighting it and I was right in the middle of it. I have hiked up parts of Hells Canyon and I know I didn't make it up as far as I hiked in my jet ski... I'll have to look on a map for more details when I get home from work.