We stumbled upon this place and were surprised that no one had ever heard of it before. It has excellent sport climbing, but little trad. Many crags were exposed with the creation of an old and defunct railway line. The crags have been vigoursly cleaned for you safety and many have excellent bases. Not exactly a traditional climbers ideal spot.
The crags along the Iron Horse trail (Deception, We Did Rock, etc.) receive excellent sun, and are far better choices for the shoulder season. Amazonia and walls along the other trail are very well shaded and are likely better choices for the hot months.
There is unofficial camping along the river. Go to exit 34, drive north through the trucking area. Take a right on north fork road. Drive until you find the river. There are a number of unmarked camp grounds between the road and the river. They are not mantained, and thus are "free". The river provides water, I recommend purifying it. There are no toilets, make sure you go at the crags or in town.
There are also two official campgrounds in the area. The closer one is at Tinkham Creek, south along Exit 42 for a few kilometres. Another is at Denny Creek, along the Arkham Road Exit about 50 miles east of Seattle along the I-90. Unfortunately, when we visited the crag in late September, Tinkham was closed for the season, and Denny was absolutely full. No matter, you can continue along the road past Tinkham and use any of the unmarked pull-outs to the left for your car, and just set up camp in the forest. This is not only free, but officially tolerated - the local ranger came by and said that we could stay for up to 14 days, as long as we took down our tents during the day. North Bend (Exit 31) has a 24-hr Safeway (and Starbucks!)
What to bring
Bring American money and a passport. You will get hosed on the exchange rate if you try and use a debit card. Bring your climbing gear, camping gear (reasonably warm), and a guide book (at least a photo copy). Should talk around to share tents and stoves.
Topo's are available on-line at deceptioncrags.com