Something to keep in mind is the outcome of this cross will not be a single unique combination of the two parents. Just the same as no two children from the same parents are the same. Some are better than others
You will get a mix of plants ranging from those that are mostly like chinook, to some that are mostly like cascade and every possible mix in between. The trick is to select the oofspring that has the traits you want. I actually am working with an apple breeder to develop more disease resistant rootstock. Trees are even worse than most plants as they take up more room, and it can be several years before you know which offspring you want to keep (I'm trying to reduce this step). It is easy to grow 5000 lettuce plants to select the best, try growing 5000 apple trees
That being said - go for it. It sounds like fun. Traditional plant breeding does rely on some elemnt of luck - and a lot of hard work.