I started looking at some routes for Any%, and 100%. The former is only 10 stamps and fairly quick. Hundo requires the trophy "Splish-splash", which requires going to the powerplant area in Stanhamn to scare the worker to spawn them later in Basto for the trophy. If you start a new game with the "Jump to Post Game" option, you start with the Horn. Ultimately, you start at Homelanda, go right to Stanhamn, honk at the gulls to get the ferry across to the powerplant, go inside and scare the worker into the water, go outside to talk to them, and get the stamp.