The Druk Path trek takes 9 days, 8 nights, from Paro to Paro. It is a point-to-point walk, from Paro over the ridges to Thimphu, with the drive back to Paro on day 8. Here is how the days run.
Days 1 and 2: Paro. We meet you at the airport, a drive of 10 to 15 minutes to the hotel. The first day is easy: the National Museum, Paro Rinpung Dzong and the cantilever bridge are all close to town. Day 2 is the Tiger's Nest hike.
Day 3: Paro to Jele Dzong. About 10 km and 4 to 5 hours. The first hour and a half is a steady climb, then the slope eases and the trail goes through thick forest and dwarf rhododendron. This is the biggest gain of the trek, from Paro at about 2,200 m to a camp at 3,480 m.
Day 4: Jele Dzong to Jangchulakha. About 10 km and 3 to 4 hours through rhododendron forest, to 3,770 m. A shorter day, deliberately.
Day 5: Jangchulakha to Jimilangtsho. About 11 km and 4 hours along a ridge, to the lake at 3,880 m.
Day 6: Jimilangtsho to Simkotra Tso. About 11 km and 4 hours, past Janye Tso, to the highest camp at 4,110 m.
Day 7: Simkotra Tso to Thimphu. About 14 km and 5 hours, the longest walk of the trek. You climb gently first, then descend through juniper to a community hall near Phajoding and on through blue pine forest into Thimphu, where you sleep in a hotel.
Days 8 and 9. We spend the day in Thimphu, then drive back to Paro in the evening, so the flight morning is unhurried. On day 9 we take you to the airport.
After the first climb the nights are close together in altitude: 3,480, 3,770, 3,880 and 4,110 m. That pacing is what lets a moderately fit walker enjoy the trek rather than just get through it.