Answer 1: a three-cell route with one turn
Trace HUB through 1 at row 2, column 1; 2 at row 1, column 1; 3 at row 1, column 2. Reading those cells in order gives H → U → B. The route starts at row 2, column 1 and finishes at row 1, column 2, using exactly the three cells required by the shortest answer.
From row 2, column 1, move up to row 1, column 1, then turn right to row 1, column 2. That produces one upward move, one rightward move, one turn, and two straight segments. All three cells touch an outer edge, and row 1, column 1 is the route’s single corner visit. After this word is assigned, 15 open cells remain for the other three answers.