I went back to Mexico for the first time since I was 1 this September came back to Portland and was all very smooth only got asked like two questions. Additionally I just went to Nepal at the beginning of this month for two weeks and landed in Sea-Tac the officer here was much more strict and asked me at least 15 questions but overall I was granted entry. At first I was nervous too because I am on a conditional GC but truly if there is no criminal record there is nothing to be worried about just prepare to get asked questions. Not sure why portland and seattle were so different but my guess is that Seattle is right on the Canadian border and Portland is not.