Well John you would certainly have your work cut out for you if you do with trout patterns what you have done with saltwater patterns.
For a basic but still fairly inclusive fly box I would include the following:
Adams, 12, 16
Light Cahill, 12, 16
Blue Wing Olive, 12, 16
Royal Wulff, 10, 12, 16
Royal Coachman, 12, 16
Adams Wulff, 10, 12, 16
Elk Hair Caddis, tan and olive, 12, 16
Yellow Humpy, 12, 16
Baetis and PMD Comparadun, 16, 18
Tan, Cream, and Black Midge, 20, 22
Black Ant, 12, 16
Yellow Stimulator, 10, 14
Hopper pattern, 10, 14
Bead Head Hairs Ear, 12, 14
Bead Head Prince, 12, 14
Bead Head Pheasant Tail, 12, 14
San Juan Worm, 10, 14
And if you are going out west you would do good to tie up things like the bitch creek, the montana stone and various other stonefly types. There that ought to keep you busy.
BTW if you are fishing nymphs with an indicator and the fish are occasionally hitting the indicator (it's happend to me many, many times) putting on a yellow humpy or stimulator will often bring that fish up.