Rhode Island girl touring one coastal region (7)
I believe the answer is:
riviera
'coastal region' is the definition.
(I've seen this before)
'rhode island girl touring one' is the wordplay.
'rhode island' becomes 'ri' (US postal abbreviation).
'girl' becomes 'vera' (**).
'touring' indicates putting letters inside (touring can mean going round).
'one' becomes 'i' (Roman numeral).
'vera' enclosing 'i' is 'viera'.
'ri'+'viera'='RIVIERA'
(Other definitions for riviera that I've seen before include "French/Italian Med. coast" , "Coastal region between Cannes and La Spezia" , "I arrive at French holiday region" , "I arrive at rich resort in Southern France" , "In France, the Cote d'Azur" .)