If Gabbard doesn't go GOP, will she join the Constitution Party, or the Forward Party?
The Constitution Party hasn't been even vaguely relevant since like 2006, and I doubt that she would fit in with the Forward Party's particular brand of weirdness. I think she's going to stay independent, though I doubt she runs for anything again.
I'd say it was pretty relevant in 2008-2010, Basically sinking Gordon Smith in Oregon and getting a lot of support with Tancredo in Colorado. They're looking to make a comeback their RV's have gone up 50% since Trump's election.