Once great, ruined by population growth
I have lived in Longmont, Boulder are since 1970. I recently left the state. For so many years, Longmont, Boulder and Colorado were one of the most wonderful places on the planet. However, It has all changed dramatically. Colorado's population has quadrupled since then and things are different now. Longmont has horrible traffic and apartments are going up everywhere. The close in rural areas are now residential construction zones. I25 has been expanded but as soon as they add a lane, it gets choked with more cars. The outlying rural towns and areas have become residential clusters with shopping centers.
When I moved there in 1970 you could camp anywhere, anytime. Now, don't go on weekends and reservations are required at many places. If you like to ski, there are many great ski areas.However, skiing has become very expensive and the weekend traffic to the ski areas is horrible. Ski on weekdays, it's better.
Boulder used to be a nice town to get around in but high density apartments, and business building has made it a constant traffic jam. The Boulder mall is still a great place.
Over the years winter has warmed and the summers are hotter. Many days near or just over 100 degrees. Between winter and summer heat, the comfort zone is not that long. In the summer, there is a caravan to the mountains, so expect a slow go. There are lot of sunny days.
Longmont and Boulder are great about building parks and bike trials / multi-use trails and that is a big plus. As with so many places, the area has been impacted negatively by the constantly growing population. I would live in the old Boulder / Longmont but not the current one. I now live on my sailboat in Ventura California but I am still looking for my final location.
Steve | Oxnard, CA