First, I am not a writer. I do not know what writers go through to complete a story. So this is not criticizing in any way. It is just an observation and opinion from one reader.
I love the story the first time I read it. I enjoyed it again the second time I read it. But I started to notice inconsistencies in the dates.
The more I look for the more I found. I really loved this story. So they might not have been that bad.
Once seen cannot be unseen.
First, when did the gates first appear was in September or October. Different times throughout the story it could pointed to either.
Second several specific dates were mention throughout the story and the timeline between those dates do not match up.
SPOILER
Jason mentioned going solo in his green gate twice. Nine days the first time, five days a second. He then took the girls in three times, and once with Heather that makes six times in his green gate. Not possible and still be on the first floor.
When the team acquired the second green gate they went to do five runs. If each run took four or five days with a 10 day cool down. It would take 2 1/2 months to do the run. If they left beginning of June they would not get back to Chicago till the middle of August when Jason was going to Washington DC. Yet they made it back and they were able to do several more runs.
So many more runs were done during the time frame than possible.
Once seen cannot be unseen.
I will have a hard time rereading this story again. And if he does come out with a part two, I am afraid a timeline will be in the forefront of my mind while reading it.