Rhode Island girl touring one coastal region (7)
I believe the answer is:
Here is my best explanation:
'coastal region' is the definition.
(I've seen this before)
'rhode island girl touring one' is the subsidiary indication.
'rhode island' becomes 'ri'.
'girl' becomes 'vera' (**).
'touring' means one lot of letters goes inside another.
'one' becomes 'i' (roman numeral).
'vera' placed around 'i' is 'viera'.
(Other definitions for riviera that I've seen before include "Mediterranean playground of the rich", "Coast of S. France/Italy", "Resort area", "I arrive at rich resort in Southern France", "Mediterranean coastal region", "Mediterranean French/Italian coastline", "holiday destination", "Coastal area between Cannes and Italy", "I arrive at southern resort area in France" and "French Mediterranean holiday area".)