Work with a local business . You may be able to pay a local business to park your car in their parking lot. If there is a 24 hour store around you may be able to leave your car there, but check with the management first. Most malls and stores have a tow away policy. Park at a manned entrance .
Some parks even close the gates in the evenings.
All of these elements are things that thieves do not like. You can hike in from a more secure location. Take a Greyhound Bus . Greyhound stops in some very remote locations and small towns. You may be able to take a bus close to your trailhead and walk from there.