The missing letters are T, H, U, N, and Y.
Determining the first letter:
H cannot be next to W, from the top right.
H cannot be next to C, from the C near the middle: it would need to be connected to both adjacent Hs, making a set that's too large.
H cannot be next to *, from the top middle.
So H must go on the far right of the circle.
Determining a second letter:
U and Y cannot go in the bottom-right question mark (between H and *), or they would give a set that's too tall in the rightmost two columns. T cannot go there either or it would join the top-middle and top-right groups. So that letter must be N.
And a third:
T cannot go in between C and E, because it would make the top right group too big.
T-Y-C makes the leftmost group too tall; W-T-U-C makes the top middle group too tall. So T must go left of C.
And a... problem:
I may be missing something, but the puzzle appears to be ambiguous. U and Y can be flipped and both will lead to a solution.
It's pretty clear that the second is the intended solution, giving what the locals think of the place: they love it!