From Colorado 160, east of Alamosa, turn north onto Colorado 150 toward Great Sand Dunes National Park. Drive over 3 miles and turn right onto Lake Como road (aka Blanca Peak road). The type of vehicle you are driving will determine how high you can park. Most cars can drive about 1.5 miles up before it gets rough. 4WD SUVs and trucks can slowly make it 3.25 miles to several pull-offs at 8,800', before the road turns nasty. This is a popular parking spot and almost gets you to within 4 miles of Lake Como. If you have a high-clearance, small, 4WD vehicle you might be able to drive to 10,000' but you'll find very few places to park. An ATV, UTV or modified jeep/crawler can get to Lake Como, depending on the driver.
Notes
2WD to 8,000' on the Lake Como Road.
Moderate 4WD to approx. 8,800', just inside the USFS forest boundary.
Rough 4WD to approx. 10,000' but very limited parking.
Severe 4WD above 10k to reach Lake Como.
