It is a pretty drive up Boulder Canyon up to Eldora. Usually traffic isn't a big deal. You can take the bus from the Boulder RTD station up there. I think it's the N route. It will drop you off right in front of the daylodge. This is a good option if you are into apres-ski. If you drive I would take in some of the local flavor in Nederland esp. during Frozen Dead Guy Days.
Eldora is big enough for a few days of skiing. Corona Bowl is nice. The big drawback to Eldora is the wind. Every time I go there I am practically blown off/down the mountain. The jet stream hits the local 14-teeners and just howls up there. It can be icy sometimes too. They do have a wonderful X-country center with ski and snowshoe rentals. They have a nice trail system. Check it out and have fun.