If this were happening in my back yard, I would raise awareness as much as possible. Don't just e-mail your local PD a comment from their web page. Have several people show up at different times to make a report in person. Bring photos, GPS coordinates, maps, statements. Insist that you have to get a report for insurance. Have everyone who took damage do the same.
It is very important that you make Law Enforcement's work as easy as possible - they are limited in terms of time and resources. But you must be persistent and having people make multiple visits puts a lot more pressure on agency folks to do something.
Make sure you emphasize your fear for life and limb ("There's a youth hunt scheduled for next week! My kid rides our quads with mom on that trail! He could have been killed!") Do not let your concern be talked down to a "simple vandalism" complaint.
Do the same at the local BLM or USFS office. Follow up and make sure you get copies of each agency's report if they are willing to release it. If not, ask for the case/report number and a contact. While you are visiting in person to follow up, make sure to give each agency a copy of the other's report, case #, detective's contact info, etc. They may not talk to each other unless you facilitate it yourself. Keep visiting to drop off any new leads you get. This keeps your issue on the front burner at the station.
Next, call the local paper. Get it on the local news. Call as well as visit the county supervisors or city council offices. Post up flyers - both in the nearby towns and on the trails. Install a game camera or 3 and try to get some photos. Consider publishing anything you have. "Red Ford F250 with a green winch bumper - Call 911 immediately if you see it!" is better than a flyer with no actionable info. Put the case number and the lead LEO contact on the flyers.
If good leads come your way, don't make contact with anyone involved. Get these to Law Enforcement.
Make sure to keep your own log of any leads, contacts or game camera activities. LEO will need to establish a timeline and "chain of custody" for everything if the perps go to trial.
If you can, get a reward fund together. If some folks in your Jeep club are mad and have somewhat deep pockets, post a reward that is well more than it should be worth. Like in the $1000-10000 range.
And don't settle for posting 10 flyers. You want hundreds. You want to make it look like the whole county is on a manhunt and ready to kill or capture them if they so much as drive by the Walmart in their out-of-state cousin's rental car.
This probably won't result in their immediate capture and punishment. But eventually, the responsible party or someone who knows them will see all the attention. They have to get gas, buy groceries, and use those roads themselves. Peer pressure or nervousness from the publicity will likely make them knock it off, at least for a while. This is as much "PsyOps" as it is anything else - making the public aware of what these jerks are doing, and using popular opinion to get government resources and community pressure on it.
Remember, stalkers, sociopaths and other jerks like to work in private. They like it when their victims keep quiet. Bringing a massive magnifying glass over their activities on Rural Route 1 in East Bungraper County, OK will make life hard for them. Even maladjusted people hate feeling like the community is watching them 24/7. And being ultra-public also means there's no single person that they can vent their anger on.
I've been through this process before. A polite but very tenacious campaign will get results.
Arclight