The map below shows the most straightforward way to get to I25 North from DIA. After leaving the tollbooths, you will be on Pena Blvd., which is really at this point a controlled-access highway. Take this to the clearly-marked Tower Road exit, and head north (i.e., make a right turn onto Tower Road). Go several miles north to 104th Ave. and head west (left turn). Now it's a ~10 mile trek to I25, where you will head north to Fort Collins.
Driving North on Highway 25, you will approach Fort Collins, go past the Harmony and Prospect Road exits and take the third one, Exit 269 and head west (towards the mountains!) about 5 miles into town. This road becomes Mulberry St. You will soon come to a large street, College Ave with a Safeway Store on the corner. Turn left (south), and go to Laurel St., where you will make a right (heading west). As shown on the detailed map, in only a few blocks you will come to Howes, where you turn left into the CSU campus. Bear to the right, and make the gentle right turn into the parking areas. You may want to drive through the first small lot and park in the big one. The Physics Department entrance is in Wing D of the engineering building, next to the large white liquid nitrogen tank.
