The walk to Theth is an absolutely gorgeous day hike, which takes you through a wide valley, and up a steep ascent to the Valbona Pass (1838m) before a descent through thick forest into the Theth Valley. The views throughout are spectacular, and there are even a couple of small cafes en route, where you can stop for cold drinks in the sun and to enjoy your packed lunch.
The Valbona–Theth hike takes roughly five to six hours. It’s worth getting a lift to the trail-head (a couple of kilometers beyond Valbona) as it’s a tiring and monotonous walk over a dry stone riverbed otherwise. The trail is decently marked, with a couple of places to stop on the way for food and drinks. It’s easy to hire a horse in Valbona to carry your bags if you’re carrying significant weight. It’s also possible to hire a guide for the route. You can overnight in both Valbona and Theth.