Deefer, one place to look is the websites of the local newspapers where you think N56200 was or should have been prior to Winslow.
Searching for TCT reveals hundreds of results but a narrow search can reveal more. e.g this report states she was in Santa Monica 11th May 2016
Aviator Tracey Curtis-Taylor close to completing historic US airmail route | abc7.com
You might be able to piece together a timeline or at least use the info to verify FB/Twitter post timings.
