Boulder or Keystone?

Neither is a place to swim in any serious way, but Boulder at least gets you into the water in summer. It has a small sandy swim area at Boulder Reservoir, and you can float down Boulder Creek on an inner tube. Dillon Reservoir below Keystone is fed by cold snowmelt and mostly closed to swimmers, so it is for sailing and paddleboarding, and a swim there means a hotel pool or hot tub.

Boulder eats noticeably better. It has seasonal farm-to-table cooking, plenty of vegetarian and vegan choice, good bakeries and coffee, a Saturday farmers' market by the creek, and tea at the hand-carved Dushanbe Teahouse. Range is still thin, and serious eaters head to Denver.

Keystone's food is resort food: slopeside grills, pizza and après-ski burgers, plus a few more ambitious rooms, one of them reached by gondola. Many visitors cook in their condo or drive to Frisco or Breckenridge. Both places pour good Colorado craft beer.

Boulder has enough to fill a pleasant day of sightseeing, while Keystone has almost nothing. In Boulder you can walk through the wooden cottages and auditorium of the 1898 Chautauqua below the Flatirons, then cross the university campus with its sandstone walls and red-tile roofs. Up on the mesa is I.M. Pei's atmospheric research laboratory, which has free exhibits.

Keystone was built for skiing in the 1970s, and River Run Village is modern and practical rather than something to look at. The area's history lies outside the resort, in the old mining cabins and ruins of the Snake River valley and the Victorian towns nearby.

Boulder offers a modest but real night out, with brewery taprooms and cocktail bars around Pearl Street and loud student bars on University Hill during term, and Denver is close for more. Keystone's evenings centre on après-ski at River Run and end soon after dinner, so anyone wanting more goes to Breckenridge's Main Street.

Both places are superb for the outdoors. The difference is that Boulder's trails start at the edge of town, while Keystone's mountains start at the lift. From Boulder, a protected ring of open space runs from Chautauqua up to Bear Peak and the mesas, Eldorado Canyon offers serious rock climbing ten minutes away, and cyclists train on the canyon roads. Rocky Mountain National Park is about an hour's drive.

Keystone sits far higher, at about 2,800m, in true alpine country. It has bowls well above the tree line, and Arapahoe Basin is just up the road. In summer you can climb Grays and Torreys Peaks, two of the state's highest summits, walk the tundra at Loveland Pass or sail on Dillon Reservoir. The thin air takes a day or two to get used to.

The choice of outings is broadly similar, but it points in different directions. From Boulder, Denver's art museum and Union Station are an easy bus ride away. Most other trips, such as Golden, Fort Collins or Estes Park, need a car.

Keystone has more variety close at hand. Breckenridge's Victorian centre, the Georgetown loop railway, Leadville's mining-boom streets and Vail's village are all within an hour. Denver, though, is a longer drive and can be slow on winter weekends.

Keystone is better set up for children, at least in winter. It has a big ski school, gentle lower slopes, a snow fort on the mountain, a huge skating lake and condos a short walk from the lifts. Off the snow there is less to do.

Boulder is relaxed and safe, with creek paths, easy trails, tubing, the planetarium and street performers on Pearl Street. Its zoo and aquarium days, though, mean going to Denver.

Boulder is a compact town you can walk and cycle, while Keystone is a resort of separate bases linked by shuttles. In Boulder, downtown, the campus and Chautauqua are close together, and off-street bike paths run along the creeks. At Keystone, free shuttles connect River Run, Mountain House and Lakeside, and free county buses go on to Frisco and Breckenridge.

Each has its catch. Boulder's trailheads outside town and the national park really need a hire car. Keystone's problem is getting there in the first place: the drive up I-70 from Denver can bring chain rules and slow weekend traffic in winter.

Boulder is the better place to browse. The brick-paved Pearl Street Mall has independent bookshops, galleries and boutiques, and its climbing and cycling shops are unusually good. Keystone has rental shops and a few stores in River Run Village, and its real draw is the outlet centre in Silverthorne, ten minutes away.

Keystone costs more than Boulder, above all in ski season. Lift access, equipment rental, ski school and slopeside rooms add up quickly, although free buses, condo kitchens and the supermarkets in Dillon help. Summer is gentler on the wallet.

Boulder's hotels are still dear and its restaurants charge affluent prices. But its main attraction, the trails and open space, costs almost nothing. Many visitors also save money by staying in Denver and coming in for the day.

Boulder has much more live performance. Small rooms downtown book rock and bluegrass acts most nights, and in summer the Colorado Music Festival plays in the wooden Chautauqua Auditorium and the Shakespeare festival performs outdoors on campus. Red Rocks Amphitheatre is about 45 minutes away.

Keystone's offer is mostly summer festivals on village stages and concerts by the reservoir at Dillon. A professional theatre company in Silverthorne adds plays and musicals all year.

Boulder makes wellness a way of life. It has yoga and meditation studios everywhere, a contemplative university tradition, massage and acupuncture, and an unhurried morning rhythm, with a spring-fed pool at Eldorado Springs in summer.

Keystone's version is recovery after skiing: resort spas, plus outdoor hot tubs at almost every lodge where you can sit as the snow falls. For real hot springs, both send you to Idaho Springs.