Wheels, chains, and cassettes

[DebW]

I plan on putting outside wheel on bike today with new cassette and readjusting alignment. Then I will move new cassette to my indoor trainer wheel and see how much "different" it is -- have a feeling my adjustments will be MUCH less because I won't be trying to get rid of noise and the chain/cassette combo will run much smoother.

Do you feel I should throw away the old cassette? Or is it good for some future project?

Might as well throw that old cassette away. Unless you want to swap chains and keep using the old chain with it. But it's worn and even with the old chain won't last much longer.