Not many fish in the river yet. I was out last weekend (casting practice?) and the smoke was nasty. Doubt it affects the fish much.
Back to the OP, it's a big river: my advice, which was given to me, is to pick a particular stretch of river that looks good (confirmed by others being there too) and fish it until you know it well. High water, low water, whatever, figure out that stretch and build on your knowledge slowly. Unless, of course, Poppy tells you which rock to stand on - but he usually says find some froggy water and fish it.
For flies, try small, sparse, dark flies with just a bit of bright color in there somewhere. Every fly I have caught a fish on in the CW has had black in it, except for the Lady Caroline. Very early in the morning you might use something with a bigger profile, fished higher up in the water column. Try a skater too, if you are feeling cocky, early in the morning. You will not need a tip until December, and even then can do without.
See you out there, through the haze!