One day
Start at Nidaros Cathedral when it opens, before the day-trippers, for the west front, the nave and the Archbishop's Palace beside it. Walk up through Midtbyen to the Torvet main square and past the Stiftsgården wooden palace, then head down to the river and cross the Old Town Bridge into Bakklandet. Wander the wooden lanes with a coffee and a bun, and end the day among the wharves and the riverside terraces as the light goes long.