Has Johnson (+) said anything about the TPP yet? I would assume that Libertarians lean toward "free" trade deals.
(+) He's been polling in double-digits for weeks now, three points shy of the threshold for getting in the debates. That's a "current candidate" in my book.
Libertarians lean towards free trade, but just because a treaty has "free trade" in its name doesn't mean they will believe it is a step towards free trade.