There are three river attractions that are easy to set up, one with a slight variation between the eras.
There's the river rafting that would be based on the Jurassic Park/Jurassic World rides, something rather interesting and would probably be easy for Frontier to utilize there.
You have the river kayaking tour in Jurassic World, and you have the larger boats from the Jurassic Park artwork behind Hammond (Seems to be based, somewhat, on a more modern version of the boats used in Disney's Jungle Cruise rides).
Theoretically, Frontier might be able to get some funds for this from Universal as well, market it as a cross promotion DLC (or free update would be nice) that includes the rides (essentially a new buildings, vehicles, and gates, but largely reusing the vehicle setup for the gyro and other similar tours) along with the Ultrasaurus and Psittacosaurus as potential dinosaurs using the looks of the models.
The gates could add an alternate gate option for tour vehicles that's a short, rock tunnel that could be used with any of the tours.
Mention that it's based on Jurassic Park: The Ride and Jurassic World: The Ride while cross promoting them, perhaps Universal could try for a trip giveaway for some players as well, and in the shops at the theme parks, well, having things for the games placed there or having a Frontier event there for it similar to the one in the UK for RTJP that several youtubers did, but having it also be more open to visitors, which would draw people to the park as well...