UPDATE (5/23/17): It looks like my speculations about Trish (Gina Philips) appearing in flashbacks that would eventually lead to another film may have some merit afterall. Gina had a recent interview with Diabolique Magazine where she offered brief tidbits of her character and how Trish plays out in the upcoming movie, saying:
"This is actually not my movie. It doesn’t have a lot to do with Trish. I am in it in order to launch what happens next." Adding.. "...a lot has changed for Trish over the years. She’s a mother; she’s been through a lot."
Lastly, she goes on to say: "...the plan is for this stuff to go to the screen in the next Jeepers Creepers movie. Victor has written what happens from the second after the conclusion of Jeepers Creepers 3. I think that’s all I’m allowed to say about it but he wrote in such detail and he had a lot of flashbacks to what happened over the years that it made it very easy for me. I got to see what will eventually happen to the character and he put enough flashbacks in there that I got to see what happened to her over the last 15 years. Let’s just say, there’s more to come."
ORIGINAL POST (4/19/17): With news that the film is now in post-production fans have been trying to dig up more information on the fairly secretive project, which turns out may be more of a prequel than a sequel. A fan reached out to actor Stan Shaw (who plays the town sheriff that's hunting the Creeper) via twitter asking if it still had the subtitle Cathedral, in which he replied:
Fans may already be aware that the recent synopsis that has been floating around lately is essentially the original story for Cathedral:
Trish Jenner is now a mother of a teenage son named Darry, named after the brother she lost 23 years ago. Trish has a recurring nightmare where her son suffers the same fate as her brother did, killed by the Creeper. Determined to prevent this from happening, Trish, who is now a rich and powerful woman, sets out on a final quest with Jack Taggart Sr. and Jr. to end the Creeper’s reign of terror once and for all. The Creeper fights back in gory glory as its enemies grow closer than ever before to learning the secret of its dark origins.
But when this project was officially announced back in September of 2015, it came with this synopsis:
Jeepers Creepers 3 will show events on the last day of the Creeper’s twenty-three day feeding frenzy, as the skeptical Sergeant Tubbs teams up with a task force hellbent on destroying the Creeper for good. The Creeper fights back in gory glory as its enemies grow closer than ever before to learning the secret of its dark origins.
Fans may remember Sergeant Tubbs played by actor Brandon Smith in the first movie, which essentially means the story will continue sometime after the first and knowing how the second ends, can't take place afterwards, so the story is obviously set between the two.
For some reason along the way of reporting on the movie the two plots kind of meshed together, and most of Cathedral's storyline bled over to the current premise. However, now that Shaw is saying it's a different film than Cathedral, it seems like the initial plot that came with the announcement is the more valid one.
Meanwhile, an even older tweet from actress Marieh Delfino (Rhonda Truitt from the second film) adds more weight to this being a prequel, where a fan was sad she wasn't returning for this next installment, in which her reply was:
Additionally, when still in production casting calls were sent out that made sure to point out that they're looking for people with vehicles no older than 2001:
So what does this all mean? All the evidence seems to suggest that the storyline takes place between the two movies and the original premise following Sergeant Tubbs is the real synopsis. But how did the storylines get mixed up? If you take note of the Product Description above, you'll see a brief tidbit on the story, indicating that Trish is now a mother and teams up with "witnesses to a murdering spree" to end the Creeper once and for all.
If we take in account that recent rumors are saying that actress Gina Phillips (Trish) has a cameo appearance instead of a starring role, perhaps the movie starts off as a sequel, where Trish is in fact a mother and is worried that the Creeper will return. Maybe then we flashback to the events that take place between the two movies and then we return to the older Trish where she finishes the job. Then again, maybe it starts off between the two movies and the older Trish only shows up at the very end.
Either way, given all the information it seems that the movie is primarily a prequel that may lead into a sequel with an older Trish finally finishing the job. This would make sense since the Creeper went into hibernation before being killed in the sequel and this is said to supposedly be the final installment, which would come full circle if Trish got to finally have her revenge. Unless Trish only shows up at the very end to lead things into a fourth film... Until a trailer or something official is finally released, we can only speculate. You can find more info on Jeepers Creepers 3 here.