The Lower Deschutes is another spot that is exceeding expectations lately. I say that from the standpoint of how hot it’s been yet the trout fishing just keeps churning out good days each time we go. Tonn had an 11 year old in the boat this week who landed 8 big redsides just at the 1st stop of the day alone. All on Perdigons. 
Our shop guy and my good friend Gavin aka Camp Sherman Dad was down the 3 day stretch with the family earlier this week and he found the morning and evening dry action to be very good on spent caddis and rusty spinners with some hatches of PMD and Caddis going on and off throughout the day. He also observed spent moths in the eddies and said he fooled the fish with a #16 tan x caddis without any floating on it. I love stuff like that!
other Dries you want will be Black Micro Caddis, Purple Haze and Yellow Sparkle Duns. 
Nymphing Caddis Pupa and Soft Hackles, Stonefly Nymphs and basics like Micro Mays, 2 Bits, Psycho Prince and Copper Johns will be good under the indicator. 
Trout Spey streamers, leeches and Brown TJ Hookers. 
Steelhead run numbers coming through the dams on the Columbia are more impressive at Bonneville than the Dalles Dam. That tells me we are getting some fish in the lower river which is good, but a lot more are to come shooting through when it cools off and they decide to push through the Dalles and up the Deschutes. I am confident this October and November are going to be very good for steelhead on the day stretch and if you have an interest in getting down the Lower River this fall, get booked soon.