If you're in Boulder, yes, I think you could easily do without a car. Well, not entirely easily (wrangling kids and groceries onto a bus isn't nearly as easy as taking the bus solo!), but yes, it's do-able. When I go to Boulder, I rarely drive unless I'll be bringing back something that requires a car. I've taken my bike on the bus a ton of times and it's very easy. Also, most of the time when it snows I'd rather be on a bus than in my car. There's only one time when it was a dicey situation but people in cars were getting stranded all over the place that day so it's not like I would have been better off if I'd driven to Boulder that morning. They ended up closing several major highways that day because of the amount of snow and the number of stuck cars made it impossible for anyone to get through or even clear the roadways. (The good news is that we only get a good blizzard every couple of years!) The first four years that I was at CU-Boulder (as a grad student and teaching classes) I *never* drove, or at best I drove to a park & ride and caught the bus from there.
If you live in one of the nearby towns, it really depends on where you end up. If you manage to live within walking distance of a grocery store or Super Target or something, then it's manageable year-round. We have pretty mild winters here overall (December tends to be
but January often features 50-degree days...and then all the snow comes in March!), but obviously, if we had a snowy week it could make getting to the store difficult.
You might want to check out the RTD website (http://www.rtd-denver.com
) and look at the route map for Boulder and nearby towns so you get an idea of where the bus could take you and what's within walking distance in a given town. Some towns are more walkable than others. Sometimes it's hit or miss. I live in Westminster and can walk or bike to the library and two natural grocery stores easily (two more regular grocery stores easy too), along with a Target and other shopping, but not all parts of Westminster are like that.
Parts of Broomfield and Lafayette are very walkable like that too--in close distance to libraries/parks/bus lines/grocery stores, so it's possible if you're in the right spot.