Alan,
I share your sentiments. Although I am a non-Coloradoan, I have vacationed there numerous times since the early 80's. Back then I was captivated by the mountains and the rustic charm of unspoiled countryside. The last several years what you say has happened around your Aunt and Uncle's mountain retreat has been occuring up and down the Front Range, and now seems to be accelerating. From the NM border to North of Loveland, from the high plains to the western slope, the mountain 'wilderness' is rapidly retreating to the desert land of the Great Basin. Even out there, were there used to be nothing but sage and antelope, there are ranchettes popping up along every road. I don't know the answer if there is any, but it is getting harder to find undeveloped areas that aren't fenced in, locked up or built on (or bulldozed). Sad, for sure.