I want to go somewhere that I've never been to before
I want to go somewhere new
I want to go somewhere that I've never been to before=行った事ないところに行きたい
I want to go somewhere new=新しいところに行きたい
例:
I want to go somewhere we've never been to for our next vacation=次の休みは私達が行った事ないところに行きたいと思うんだ
Don't you want to go somewhere new and exciting this summer?=今年の夏は新しくてわくわくするところへ行きたくない?
Good luck!