Take the Highway 9 loop, past Dillon and through Keystone up toward Araphoe Basin and over Loveland Pass. The 11,990 foot summit marks the Continental Divide. All watershed on the West runs to the Pacific and the East runs to the Atlantic. The view from the top is spectacular. If you want to go higher, there are several trailheads here.
Take the Highway 9 loop through Dillon and up over the Loveland Pass for spectacular views. The trip takes about 45 minutes and bypasses the Eisenhower Tunnel (beware: large trucks carrying flamable loads use this route) and goes from about 9,000 feet to nearly 12,000 feet.