RTD buses serve Boulder and Longmont, there are routes between Boulder (Williams Village) and Longmont (Raintree Plaza Hotel Conference Center).
The M bus ($2) goes between the 2 cities about every half hour between 6-8AM and 2-6PM Monday through Friday, and about every hour between 8 AM and 2 PM and between 6-10:30PM. Service on the weekends is about every 2 hours between 6 AM and 7 PM. The Raintree is between the Twin Peaks Mall stop and Sunset Road stops, and must be requested. The M bus does not go to campus in Boulder, but only as far south as the RTD Boulder Station at 14th and Walnut. To get to Williams Village, walk to Broadway and take the Skip ($0.75) which runs about every 10 min between 5:30 AM and midnight. It is also possible to go directly between the Boulder Station and Williams Village with the 203 or 225 RTD bus ($0.75) of which one runs about every 15 min in peak hours (6-9AM, 4-6PM) and every 30 min inbetween, and every hour up to about 11PM. Ask for a transfer from whatever bus you start on so your total fare is $2. Have exact change ($1 bill and 4 quarters is best). The last M buses Monday-Friday leave Twin Peaks Mall at 9:31 and 10:31 PM. There is also a local Longmont RTD service, routes are labeled starting with a `3', i.e. `3xx'.