I don't believe he specified were the roadtrip goes, but the boat he is going on in the flashback has "Coast City" on it. I feel like we will get Hal in flashbacks, along with Ferris Air supporting characters (Carol, Tom, others?) I do have to wonder if they would also show him in present day though, doubling down on character development.
Overall, Season 3 was a bit aimless, but still mostly enjoyable. A lot of characters did seem the dumbest that they could have possibly been, but Laurel is not totally garbage anymore and Ray is good fun. Disappointed that so many characters were written out of the show. The Brick story line in the middle of the Season was a highlight to me. Also, all of the crossovers with the Flash seemed to work out pretty well.