Napa or Sun Valley?

Neither place is a beach destination, and both are far from a swimmable coast. Around Napa, swimming means a resort pool in the summer heat or a drive to Lake Berryessa, a large reservoir in the eastern hills where locals swim and boat. The Pacific at Bodega Bay is for looking at.

Sun Valley's best swim is Redfish Lake under the Sawtooths, an hour north, which has a real sandy shore but cold mountain water even in August. Heated outdoor pools are the dependable option there.

Food is the main reason to choose Napa over Sun Valley. The valley gives you tasting rooms along Highway 29 and the Silverado Trail, nationally celebrated kitchens in Yountville and St Helena, and the Oxbow Public Market in town, all supplied by the farms around them.

Ketchum does well for a resort of its size, with trout, lamb and elk on the better menus and busy breakfast spots on ski mornings. It has nothing like Napa's depth, though, and some kitchens cut back in the quiet seasons. Neither is a place for cheap street food, but Napa's taquerias at least give it an option at the low end.

Neither town is built for sightseeing, but Napa has a little more to fill a day. It has the 1880 opera house and the Victorian buildings on First Street, contemporary art at di Rosa in Carneros, and the stone wineries and old main streets of St Helena and Calistoga.

Sun Valley's interest comes down to one story: the 1936 railroad resort with the first chairlifts, and Hemingway's last years in Ketchum. An afternoon at the Lodge, his grave and the memorial covers it.

Both go quiet early and neither has clubs. What differs is the mood. A Napa evening is a long dinner followed by a glass in a downtown wine bar or a riverfront cocktail bar, and San Francisco is an hour away for a proper night out.

In Sun Valley, going out means après-ski in Ketchum: saloons and hotel lounges full of skiers off the mountain, the odd band on winter weekends and a couple of western bars that stay loud until closing.

Sun Valley is the stronger choice for anyone travelling for the outdoors. In winter, Bald Mountain's long, steep runs start from Ketchum's streets, with Nordic and backcountry skiing nearby. In summer the same hills give singletrack for biking and hiking, the Sawtooths an hour north add alpine lakes and climbing, and the Big Wood and Silver Creek draw fly fishers.

Napa's outdoors is gentler and more cultivated: dawn balloon flights over the vineyards, cycling on the flat valley trail, redwoods in Bothe-Napa Valley State Park and the climb up Mount St Helena. These fill a pleasant morning between tastings rather than being a reason to come, and summer heat pushes them early in the day.

Napa wins clearly here. Yountville, St Helena and Calistoga are short drives up the valley, and Sonoma and its mission are about half an hour away. Healdsburg and the Russian River are within an hour, San Francisco is reached by car or by ferry from Vallejo, and Sacramento is a little further.

From Sun Valley, most outings head into the mountains. The nearest places worth a look are Hailey's old main street and the log-cabin outpost of Stanley. Shoshone Falls is about two hours south, and Boise is too far for comfort.

Sun Valley is the easier choice with children, especially ones who ski or like being outside. The beginners' hill away from the main mountain, a well-run ski school, summer bike paths, horse rides and an outdoor ice rink keep the days full, and Ketchum's quiet streets are easy to manage. Rainy days and teenagers who don't ski are harder.

Napa is built for adults. Tasting rooms and long dinners bore children, and the drives between wineries and the summer heat wear out small ones. The animal park in Vallejo, the geyser near Calistoga and the hotel pools will fill a day or two.

Sun Valley is easier without a car, at least within the resort. A free bus links Ketchum, the village and the lift bases, and many skiers never drive all week. Trailheads, the Sawtooths and the hot springs still need a car, over long roads that can be snowy in winter.

Napa's walkable downtown ends quickly. The wineries are spread over some 50km of valley, and the buses are too infrequent to rely on. Since tasting and driving do not mix, a day out usually means hiring a driver or joining a tour.

Napa has more to buy, and most of it is wine, shipped home by the case from the cellars you visited. There is also olive oil and kitchenware at the market hall, design and cookware stores along St Helena's main street, and an outlet mall for familiar brands.

Ketchum's few blocks lean towards fine and western art galleries, specialist ski and fly-fishing gear, and cashmere and western wear for second-home owners. It is a narrower and pricier mix.

Neither is a cheap trip, and the costs come from different places. In Napa you pay for luxury hotel rooms, estate tastings, special-occasion restaurants and the driver a tasting day needs. Chain hotels further south, taquerias and smaller cellars soften the bill.

In Sun Valley, lift access and room rates set by the second-home market drive costs, and there is little budget lodging in the valley. The free buses and the quiet spring and autumn months are the main ways to save.

Summer is the best season for performances in both, but they take different forms. Sun Valley's highlight is a professional orchestra giving free concerts in the pavilion by the lodge for several weeks, with picnics on the lawn and figure skaters on the outdoor rink. Outside summer there is almost nothing.

Napa's offer is smaller and more varied: concerts and comedy at the 1880 opera house, touring bands at a restored Art Deco theatre, a summer classical festival at winery venues and a large rock and pop festival each late spring. For serious opera or theatre, San Francisco is an hour away.

Napa is the better place to unwind on purpose. Calistoga has been a hot spring town since the nineteenth century, and its mud baths and mineral pools are the classic end to a day of tastings. The resorts in Carneros and the hills have large spas, and the valley's routine of late breakfasts and long lunches is slow by design.

In Sun Valley, rest means mountain air and early nights. The comfortable options are the hotel spas and the outdoor heated pools, especially under falling snow. The creekside soaks up the Warm Springs valley are rough and undeveloped, and there is no bathing tradition behind them.