Trip once organised to tour new US university (9)
I believe the answer is:
princeton
'us university' is the definition.
(I've seen this before)
'trip once organised to tour new' is the wordplay.
'organised' is an anagram indicator.
'to tour' indicates putting letters inside (to tour can mean to go around).
'new' becomes 'n'.
'trip'+'once'='triponce'
'triponce' is an anagram of 'priceton'.
'priceton' going around 'n' is 'PRINCETON'.
(Other definitions for princeton that I've seen before include "Member of the 11 in New Jersey" , "Early US university" , "US ivy league university" , "where War of Independence battle was fought?" , "College" .)