Questions about the conclusion of The Killing

Obviously many spoilers here re the conclusion of the final (4th) season of The Killing: I don't think many fans of this series will be satisfied w/ the 4th season the core murder investigation is, as in the 3rd season, rather gory and preposterous, but I will say that the final 3 episodes really try to get at some aspects of the relationship between Linden and Holder, which is of course what's drawn us to this series in the first place. As they fight and turn on each other - under pressure of the investigation into Linden's execution of Lt. Skinner, the mass murderer, as the end of Season 3, we see some of the better writing and acting in the series; unfortunately, that's set against some of the crappiest writing and acting, which we see in their investigation of the Stansbury family murders and the hazing rituals as the military boarding school, a plot that we don't believe for a second and that makes little sense on examination. At its best, in the first 2 seasons that is, the series played of the Holder-Linden dialectic against an intriguing and far-reaching and for the most part realistic murder that stirred the Seattle community. The murder investigations went off the rails in the last 2 seasons, though, to the detriment of the show. Wondering what others think about the conclusion of the final season: Holder and Linden end in deep antagonism, and then we "flash forward" about 3 years and see that both have left the police force (I agree, how could they stay in after what they know and what's known about them?), Holder has broken off with what's her name his glass-of-water girlfriend but is a good single dad (yes, he loves kids and, yes, she was a total mismatch), and Linden has spent 3 years on the road - really? living how? doing what? That's not explained. She stops in Seattle to visit him, they briefly agree that their time driving around the city in her crappy car was the best time of all (echoes of Sentimental Education here? at least for me there were) and then she head off again on her solo journey - and honestly I thought it should have ended there but, no, the pressure of convention is just too great, and she comes back to him, they look at each other longingly, and embrace. Very sweet if it were an embrace as friends, but we're clearly meant to see that at long last each recognizes the rightness of their relationship - but how can we not know it will last about 10 days? that it will be all wrong? that it feels almost incestuous? No, she should be heading north to Alaska or something, not making yet another mistake and ruining what was good.