hiking
There are thousands of kilometers of hiking trails throughout the Surselva, part of the canton network of trails. The trails will take you absolutely everywhere in the region, from the river to the peaks, and are superbly marked. There are all range of difficulties from paved, contour-following paths to difficult summit ascents. For the latter the paths are graded as 'Alpine' and are marked with a blue sign. The majority of paths are graded 'Mountain' or 'Valley' and are not too challenging. Here is the link to the official mapping department of the Swiss government (http://www.swisstopo.admi...). The 'Senda Sursilvana' is a path that runs the length of the valley, staying relatively flat all the way and it runs on the northern slope of the Surselva (http://www.wandersite.ch/...). There is also an equivalent for the Val Lumnesia.
skiing
Skiing is the main sport in the Surselva region. Major resorts include Flims Laax Falera, Obersaxen and Sedrun. Flims Laax Falera (http://www.laax.com/flash...) is often referred to as Die Alpenarena. The resort receives plenty of snowfall (http://www.laax.com/flash...) and is open from October to April. It is the first resort that you come to as you head down the valley and is popular with snowboarders and freeskiers. Obersaxen in German is just past Ilanz and the base stations are situated on the lip of the hill as is Laax. Obersaxen is much smaller than Laax with only a few chair lifts, but it does have fewer crowds. Sedrun (http://www.disentis-sedru...) is the last place in the valley and has barely any crowds and is also linked to the resort of Andermatt, just over the Oberalppass. Breil/Brigels also has several lifts that link in with Waltensbourg/Vuorz a pleasant resort. Vals also has several t-bar lifts. Neither resort is particularly commercial, mainly for locals.