Welcome to the Inland Northwest and to ATP! I'm not sure exactly what the winters are like around Boise - I lived there one winter, but it was unseasonably mild to the point that the ski area was only able to open briefly by piling snow up in paths through the sagebrush. One thing I would keep in mind is the snowplow. (I am assuming you will have to have your driveway plowed at least occasionally.) Hold your trees back far enough from the driveway to give the plow dude plenty of room to pile the snow. Ditto for any fences you may put up near the driveway. You want to be ready for the big snow years as well as the average years. You can find out from your neighbors what the normal snowfall is like.
I've got a catalpa here in my zone 5 yard - beautiful trees with lovely flowers in the spring. Very large leaves which can cause a bit of a damp mat when they fall off in the fall if they aren't raked or mowed. Pretty fast growing.
Look around your neighborhood and see what trees do well and appeal to you. How much water they need and your ability to get it to them will also be a factor. Good luck with your new home and your new project!
