My favourite is Peel, as it's has shopping/cafes/pubs close by.
Like most places it fills up pretty quickly.

There are a number of campsites that open just for TT Link Here

https://www.visitisleofman.com/where-to-...motorhomes

Funnily enough, when I first went to the TT in 1976, I stayed at Peel & hated it as all the nightlife was in Douglas & I was a party animal. Much has changed since, Douglas isn't the party town it once was and I'm normally asleep before midnight these days!