The Rock's projects include Journey 2: The Mysterious Island.
New Line and Walden have had Johnson attached to The Conjuring) have reportedly set to work on penning scripts for both adventure films.
The Hayes are fresh off co-writing Johnson's 3D disaster/action film Seal Team 666 adaptation - a supernatural/action flick envisioned as a Johnson vehicle. That is to say, these four (the Hayes, Johnson, and Peyton) have clearly established a solid working relationship.
Rumor has it that Journey 3 may involve a trip into outer space, though it's probably safe to assume that such a storyline will be a tad more light-hearted than something like Gravity. If Journey 3 and 4 are going to be filmed back to back, then it's feasible the former will end on a cliff-hanger that sets up the fourth installment. It could also be that New Line and Walden would prefer to shoot theses movies together for cost efficiency, since they'll be filmed largely on sound stages with green screen backdrops.
Journey 2 grossed just over $335 million worldwide in theaters (against a $79 million budget) and was mostly successful in achieving its goal - offering a wholesome adventure story and colorful pop-out 3D effects for young ones, while Johnson and his adult costars provided some wittier banter for older folk. So yeah, this franchise hasn't exactly had lofty ambitions to date and that presumably won't change with the next two installments; as far as being decent pop art for the whole family to enjoy, though, these next two Journeys ought to get the job done.
We'll keep you updated on the status of both Journey 3 and Journey 3 as more information is made available.
Source: THR