It’s been awhile since I was an undergrad at CU Boulder but, since there are no other responses, I will try to answer some of your questions.
Firstly, congratulations to your son! The Leeds School of Business is well-regarded and has good career placement within the state and region.
In regards to life in Boulder, it is a wonderful place to spend four years. The surrounding area boasts abundant nature and recreational opportunities from hiking to rock climbing to skiing and mountain biking. No equipment? No problem! Students can rent equipment from the CU Rec Center or from one of the local sporting goods stores.
CU has a work hard/party hard atmosphere. Students are quite social and know how to have a good time. With nearly 32k undergraduates, students can easily find their people at CU. I joined the Boulder Freeride club as an undergrad and spent many weekends (and some weekdays) on the slopes with the friends I met there. My daughter found her people in the vocal music scene and in the Residence Hall Association (RHA). Neither my daughter nor I had any interest in Greek Life so I can’t speak with any authority on the atmosphere in the sororities/fraternities.
Football games are a family affair. They are well-attended by current students and the many alumni who still live in the area, many of whom have kids at CU. On Friday nights before game day, the marching band and football team “stampede” down Pearl St. It’s very festive.
The only drawback I can think of is that CU can be overwhelming both in size and geography. There are ways to make the school feel smaller (e.g. Living and Learning Communities), but students will have to seek out those opportunities. Still, there is no getting around the trek across campus. Some dorms and buildings are a bus ride away from central campus and students will need to plan accordingly especially during winter.
Hopefully, a current CU Boulder parent or student can address your concerns about fall scheduling plans.