Thanks for making that last change, Jim. Regarding the remaining definition:
.
I think "hot spring area" can suggest an area *outside* of town, as in "Jigokudani Monkey Park is a famous 
hot spring area near Nagano, Japan" -- that area would not be considered a 温泉街 because it's not a 町並み 
(as in Wikipedia's definition -- 温泉の宿泊施設や温浴施設などが立ち並ぶ町並み). 
.
And adding "e.g. within a town" also suggests that it could be outside the town (thanks to the "e.g."). 
.
I suggest that we could say it's a "district", by analogy with the term "red light district", and that we 
should remove the "e.g." since it's necessarily part of a town, and not out in the countryside.

@@ -12,1 +12,1 @@
-<gloss>hot spring area (e.g. within a town)</gloss>
+<gloss>hot spring district (within a town)</gloss>

Richard has convinced me this was misleading.

@@ -13,1 +13,0 @@
-<gloss>hot spring resort</gloss>

Maybe this is more succinct.

@@ -12,0 +12,1 @@
+<gloss>hot spring area (e.g. within a town)</gloss>

"a part of town where hot spring inns or facilities are clustered" -- I think 
that's a nice definition there from GG5, and I think my "resort" is a bit off the 
mark, since it suggests that it's the whole of the town rather than just a part.
.
How about "a part of town with a concentration of hot spring facilities and 
related businesses" or something along those lines?