Final answer
The murderer is Joe.
Step-by-step resolution of the puzzle The Hiking Trip.

There are two empty rows. Each empty row contains a bear.
Set the board to 14 rows and 12 columns, matching the grid of The Hiking Trip puzzle.

In "Edit walls" mode, draw the internal walls that divide the board into named areas (Grove, Ranger's Hut, Pine Forest, Rocky Trail, Windy Trail, etc.).

Mark the cells that cannot be occupied by any suspect: bear, tree, rock, table, and bush, as well as the exterior parts of the board in the top-left and top-right corners.

Aubrey was on Windy Trail. Mark all possible positions for her in that area.

Skip Brianna for now — we need to know where Finlay is first. Clark was on Rocky Trail, so mark all possible positions for him in that area.

Derek was alone in Pine Forest. Mark all possible positions for him in that area.

Elias was in the Ranger's Hut. Mark all possible positions for him in that area.

There was a bear in Finlay's column, 4 rows north of him. Only 3 positions satisfy this condition. Note that Finlay wears glasses, so he can also be on Rocky Trail with Clark.

Gavin was next to a rock. Mark all possible positions for him.

Hedwig was in the bottom row. Eliminate all other suspects from that row — only one suspect per row is allowed. Since Hedwig doesn't wear glasses, he cannot be on Rocky Trail. The bottom row spans 4 areas, all with room for 3 members, so we can't rule out any more of Hedwig's positions yet.

Ingrid was sitting in a chair. Only two positions are valid, since the chair in Hedwig's row can't be hers. Eliminate the intersection of those two positions — if someone were placed there, Ingrid would have no options left.

Joe was next to a bear. Mark all possible positions for him.

Kobe was in the Grove. Mark all possible positions for him in that area.

Elias and Kobe can only occupy the same two columns. Therefore, no other suspect can occupy those columns.

With the previous eliminations, only one position remains for Ingrid. Place her there.

Only one position remains for Finlay. Place him there.

With Finlay placed, Brianna's row is fixed: 2 rows north of Finlay. She can't be in Elias and Kobe's columns, or with Derek (who is alone). 3 positions remain and no one else can be in her row. Brianna wears a cap, so she can be on Windy Trail with Aubrey.

Only one position remains for Kobe. Place him there.

All of Clark's remaining positions are in the same column. No one else can occupy that column.

Derek only has two positions left. Eliminate their intersection using the same reasoning as for Ingrid.

Hedwig needs to be in an area with at least 3 people. Only two options remain: Windy Trail or the Cabin. If she were in the Cabin, she'd need Ingrid and Vincenza to make 3 — but Vincenza must be alone with the murderer. Contradiction. So Hedwig isn't in the Cabin and only one position remains.

Only one position remains for Derek. Place him there.

Two rows containing a bear also have a suspect — Brianna and Derek. By the general clue, the other two bear rows must be completely empty. Eliminate all positions in those rows.

Only one position remains for Elias. Place him there.

Each has only one position remaining. Place them both.

All of Joe's remaining positions are in the same column. No one else can occupy that column.

Each has only one position remaining. Place them both.

Only one position remains for Vincenza, the victim. Placing her also determines the position of Joe, the murderer.

The murderer is Joe.