tl;dr: Use a beater bike
By "beater bike," I mean a bike that works well enough, but isn't that expensive. It doesn't have expensive components, and has minimal street value. Something not worth stealing.
As an avid cyclist living in the New Jersey/Newark/NYC area, I've dealt with this my whole life. I've had seven bikes stolen, and countless attacks on my bikes, including seat theft, wheel theft, latches thrown, etc.
Quick story: I lost a beloved $1200 Cannondale to theft. I called the police to fill out a police report. He came down, and looked annoyed with me for wasting his time. I asked him, "Any chance of recovery?" He laughed in my face, and said, "It's probably half-way to Newark by now." Police have bigger fish to fry than chase after bike thieves.
If a thief has tools, there is nothing you can do. A sharp grinding wheel can get through a fahgettaboudit lock in about 1 minute. You can try double-locking, so that they need two sets of tools, but this will only delay an experience thief for maybe another minute.
Personal note: I would advise against confronting a thief--especially in a remote location. They can get aggressive, and may demand that you unlock the bike and give it to them. Perhaps ask for your phone, etc.
The solution is to have several bikes in the stable, for different purposes: A nice mountain bike, a nice road bike, a folding bike, and a beater.
I am very selective about where I use my nice bikes. I lock it up for short intervals (less than 1 hour), and keep an eye on it whenever possible. Whenever I go anywhere with risk of bike theft, I take an old bike that looks like it's been through a war. Works great, gets me where I need to go.
So, get yourself a decent beater bike for the mountain trails; one that you can have fun with, but is beat up and not worth stealing. Lock it up; if it goes, it goes.
You will sleep well knowing that your expensive bike is safely locked up in your home.