Powdawg, I just posted the same question to idahowhitewater yahoo mailing group and got great responses with a lot of details. You can check the archives there for the posts titled "Lower Salmon"
The key thing everyone told me: "right at 1/2 & 1/2 and HARD left at China Bar", I guess those are the biggest rapids.
Some of the other things I picked up:
1. All River Shuttle - most recommended, costs $135 per car, unless you are a teacher
2. Plan on at least 5 day trip.
3. Map: Boater Guide - Hammer Creek to Heller Bar
4. You will need Invasive sticker and Day Pass for Washington state, both sold at All River Shuttle. I think they also sell the printed map.
5. Find a camp no later than 3pm, better on the West side (shade comes earlier)
6. No fresh water fill up, bring lots of water
7. Bring lots of shade, hardly any shade at camps, but plenty of sand beaches
8. Get ready for a long lake rowing on the Snake Lake (last 19 miles after confluence)
9. Permit is self assigned at put in, regular river regulations apply (groover, firepan, take out trash/ash)
10. Watch out for rattle snakes and poisen ivy at camps
11. Do not launch if river is higher than 15,000 or 20,000 cfs (mixed reviews), the Slide rapid becomes a class V rapid, lower than that flow it's a riffle.
12. Dogs are allowed, pick up after your own dog
13. Firewood can be gathered in eddies
Hope this helps,
PS: We are launching on July 18th.