While Vail is usually a cheaper place to spend your vacation, there is no reason why you shouldn't visit Aspen while you are there. The two towns are not too far apart, after all. Aspen is just a little over 100 miles away from Vail, and the towns are connected by pristine roads that look over a gorgeous scenery.
There are three ways you can go from Vail to Aspen, and they all involve road travel. That's a problem. You see, the region is frequently hit by snow storms during the winter, and there are also car accidents and road maintenance to deal with. All of those elements can slow down road travel and cause traffic jams. If you only have a weekend or a few days to see both cities, the last thing you want is to spend 9 hours sitting in a car, waiting for a jam to be cleared.
All that means is that if you are planning on going from Vail to Aspen, you should be ready to adapt to road conditions and stay up to date on local news.
As for the travel methods themselves, you can go to Aspen using a rental car, a shuttle service, or by taking a bus. It's not hard to go from Vail to Aspen using public transport; just go to the Vail Transportation Center and hop on a bus to West Glenwood. Once there, you can get on a bus that will take you straight to Aspen.
Driving yourself to Aspen is viable, but there is the snow and the traffic to deal with, and a rental car will force you to deal with the cost of parking in both Vail and Aspen. Hiring a shuttle service, however, is simple and relatively cheap for the short trip. It's probably the best way to go from Vail to Aspen
, as it allows you to spend less time on the move, and more time enjoying your trip.