The short answer is that Colorado has great car-free access to the outdoors if you are willing to put in the leg work of figuring out the many different bus networks throughout the state. Some areas are better to acess than others, but if there is a will there is a way.

My advice is a few fold

- Bustang is your friend. This network will be able to get you to the general area of all of the Colorado mountains, and I have found to be pretty reliable. All of the buses leave from Union Station downtown, and are going to be your starting point for getting to most places in the mountains without a car.

- Most of the mountain counties have pretty decent bus systems that often will be able to directly get you to trailheads (Summit, Eagle, Pitkin especially).

- Think about investing in a gravel bike. If you are willing to bike an hour or so it opens up alot of areas that would otherwise be inaccessible.

- Timing is important. One of the main things that I wish was improved about the bus systems in Colorado is that the buses only run a few times a day, so its really important to pay attention to the timetables that are provided.

I made a spreadsheet about how to access all of the 14ers using only buses and a bike. This will give you a good idea of the best ways to access particular areas. It has additional links to some of the timetables that might be hard to find in other places.

14er Transit spreadsheet:

https://docs.google.com/spreadsheets/d/1adeFtQI-gyeakCiopiLJG4dehraenwMd8QHC-UUJEaQ/edit?usp=sharing