Roughing It (Once More)

This is part 36 of the puzzle series Around the World in Many Days. Each part is solvable on its own.

Dear Puzzling,

The numbers in blue form a Tapa puzzle. Shade some cells in the grid so that the numbered cells correctly indicate the number and lengths of stretches of shaded cells in the eight surrounding cells. For example, a “1 2” clue means there is one stretch of shaded cells of length 1 and one stretch of shaded cells of length 2 in the eight cells surrounding the clue. Numbered cells cannot be shaded, and the shaded cells form an orthogonally connected area. No 2x2 area can be fully shaded.

The numbered lines and letters in black form a crossword sudoku. Type in the answers to the crossword clues starting from the numbered cell (note that this means that some answers are written upwards or right-to-left in the grid). Then fill the grid so that each row, column and bolded 3x3 box contains the same nine letters once each. In the finished grid, the longest diagonal stretch of shaded cells spells out the final answer.

Today I have spent some more time enjoying rugged wilderness. I have taken a wildlife bus tour around a vast nature preserve and tried out the hiking trails to reach some of the more remote outlook spots with incredible views. Can you guess where I am?

1. Impressive features of Nazca
2. CIA operations base: Black –
3. Frasier's brother
4. A river in Siberia
5. A high rank in several martial arts
6. Director Villeneuve
7. Brunei's ruler
8. Surrounded with non-conducting material

Gladys will return in Musk Oxen and Arctic Foxen.

The Tapa:

The "1 1 1" clue in the bottom right means there can be no shaded cell in the bottom right 2x2. So the three shaded cells are forced.

The shaded cells must all join up, and those continuations complete the adjacent "1 2" clue, and then the "1" above. Combined with the no shaded 2x2 rule, that fores that path through the top right corner.

Meanwhile, the shaded path at the bottom must pass below the "3"s and then up the left hand side.
And joining up shaded cells from the other "1 1 1" in the top left forces the remaining path.

The crossword:

First the clues:

1. Impressive features of Nazca - LINES
2. CIA operations base: Black – SITE
3. Frasier's brother - NILES Crane
4. A river in Siberia - LENA
5. A high rank in several martial arts - DAN
6. Director Villeneuve - DENIS
7. Brunei's ruler - The SULTAN
8. Surrounded with non-conducting material - INSULATED

With those filled in, the Sudoku is quickly solved:

Finally:

If we overlap the Tapa on the Sudoku grid we get the following, with Denali on the longest shaded diagonal.

• Yup, you've got it! Nice work.
– Jafe
Commented Aug 24, 2023 at 9:46
• I really should start reading questions properly. I've just noticed "longest diagonal" instruction.
– fljx
Commented Aug 24, 2023 at 13:47