It's fantastic, with one of the most epic conclusions of any module I have run.
By that definition, I've reused-I’d describe the mileu/setting as the Campaign World and then the individual campaigns run within that.
I have used Wave Echo Cave three times. Two for Phandelver, but the most recent was an underground gangster base in the Rock of Bral. It wasn't a rushing river though; just had some standing water. I absolutely love that map. The PCs ended up going back TWICE to the map actually, so I got many, many sessions out of it in Bral.A spin-off on the thread about what modules you have run multiple times. Maybe you had a modules you run through or just used for parts, but you continued to use it for another campaign or more than one. I think I have used the Lost Mines of Phandelver (LMoP) box set for 4 campaigns. The town has now changed some and the adventures have changed, but parts keep on getting used. Cragmaw Hideout has been used by bandits, snakefolk, and the PCs in one campaign. Wave Echo Mines has come back a few times with one series trying to make it work again to enchant magic items. Another module that I used a few times was the 2e Under Illifarn which has a few short adventures and one larger one a bit like the 5e box sets. I used that a couple campaigns because the town of Daggerford was more fleshed out. Even the 4e DMG had the Town of Fallcrest that worked well, but I only used that once.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.