The most common and most likely answer to this crossword clue is the 8 letter word ENTRYWAY
I've seen this crossword clue in The Times
E
N
T
R
Y
W
A
Y
More clues leading to the result ENTRYWAY
Buddy explains!

The straight part
We know that "Perhaps US door" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case perhaps us door = entryway.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ENTRYWAY mean?
ENTRYWAY noun- An opening or hallway allowing entry into a structure.