Yeah her bluffing her way in could work.
Both the 7 and the 86 were stretching it I agree. I think the character arc is that Kim recognised their evil and repented, and tried to make amends. they set it up with her conversation with him on the phone. that plants the seed "you should turn yourself in Jimmy". The flashbacks in the last with "time machine" which is all about regrets with Walter, and Mike also set it up - they both want to make things better for people around them, he doesn't. The one example when he did help someone selflessly was the flashback to his brother. But yeah, do you buy that he could really change? The show says he does, but is it convincing? I only half-bought it as well.
I honestly think there was a subconscious element of wanting to be caught too - so he takes risks with the morons in Nebraska, and then goes into the guy's house, just begging to be caught really. I don't think finding him in the dumpster was a stretch, they knew he was on foot and where he was roughly, so obvious to look there. They did seem to know he was in there though.
Kim looked great as a brunette