If you go the legal route you’ll be way better off approaching any officials with an organized group if you have any dream to do the work and/or maintain the trail yourself. HRM will would never sign off on a MUA or LUA with an individual.
The group should probably consist of at least 1.5 university professors, preferably with earth science type backgrounds and a affinity for Tilley hats. You’ll also need at least 1.3 to 2.4 medical professionals, dentists are okay, but doctors and especially surgeons are preferred. To round out all that nerdy science you’ll want some artists, preferably ones who actually make a living through their art. A (Hali)famous tv or radio personality will beef up the presentation of your vision for sure. Law enforcement officers, lawyers, youth social workers, car dealers and contractors/developers will really add impressive bulk to the group. Hopefully at least a couple of these people will be cyclists. I suppose a few extra cyclists would be good too, but not those rowdy redbull types with tattoos, unless they clean up really well off the bike, maybe some roadies are better.
The land is already a park so be prepared for (years of?) hoops and red tape. The very least being public consultation meetings. This is where you find there will be little to no broader public support for MTB only trails and that everyone will want accessible crusher dust sidewalks in the woods.