First of all, welcome to United. Lots of us have done the desert thing, so we feel your pain. (Remember, if you sleep 12 hours a day, you are only there half as much time!)
I'd recommend bringing the wife and kids during Indoc, or at least the last week or so, to include the wings ceremony and then a few days to play in the mountains after. It is a good way to introduce them to United, too. During sim training you will get as a minimum, by contract, two days off for every 5 worked. But that does not mean those will be on weekends. You will get a full sim schedule upon arrival for sim training. You will be busy studying, but that doesn't preclude some evenings going out to dinner, or having family there during your days off if you so wish to stay in Denver instead of flying home. You will keep the same hotel room for the entire training, so you can kinda settle in for the month. Upgrades would be only if you could sweet talk into that somehow.
BTW, your Shenandoah valley plan is a good one. IAD has a nice variety of flying. Taxes are less in WV, btw.
Again welcome!