Blue pickup? Wasn't that the same color car as with the girl who escaped the attempted abduction attempt in MB? I don't think that car was described as "nice" or "new" though.
Also while we're trying to nail down the timeline IMO the Tumblr postings are in no way proof that she was at her apartment at that time. She posts a high volume on specified days (11, 14, 16, 18), without any random single postings on other days, at least in December. Point being, when I was very active on Tumblr I, and many other high volume Tumblrs I followed, would make use of the Queue feature which can post things for you in batches at a specific future date. The things posted on the 18th were similar thematically which indicates they were found around the same time from poetry tumblrs she either already follows or sought out. Unless she followed hundreds or thousands of users which she would spend a very long amount of time perusing it's unlikely she would've found all those posts at the same time and reblogged them immediately. JMO.
Edit: I see via RSS the times are kind of random. I think with queueing posts the time would show up as the same when the batch gets uploaded. So nevermind, probably!
Just lamenting about the lack of concrete timeline. Someone else posted a very good point earlier that her phone could've died for reasons unrelated to her disappearance and at a completely different time.