Came across party-goers in tweeds in odd places (9)
I believe the answer is:
traversed
'came across' is the definition.
(I've seen this before)
'party-goers in tweeds in odd places' is the wordplay.
'party-goers' becomes 'ravers'.
'in' means one lot of letters goes inside another.
'in odd places' indicates alternate letters (only odd-numbered letters).
The alternating letters of 'tweeds' are 'ted'.
'ravers' placed inside 'ted' is 'TRAVERSED'.
(Other definitions for traversed that I've seen before include "Came across" , "Travelled across zigzag course" , "passed over" , "Went over" , "Crossed" .)