Arranging loop hikes in the Cats can be difficult and annoying, especially if you want to get some good miles in.
Honestly, if you want to do the Escarpment Trail or Devil's Path and you're solo and only have on car, the best thing to do is drive to where you plan to end your hike and have a cab come pick you up and shuttle you to where you want to start. It'll cost you $20 more or so, but you get to hike the trail you want. (Incidentally, you can also take the bus all the way to the Cats and have a cab pick you up and drop you off at the trail head...but you're SOL if they forget to pick you up or you're late finishing and they drive off.)
There are a lot of cab companies in the Cats. Just Google around. Be sure to call and set up your pick up location and time before you get too deep into the woods though, or you'll lose cell signal.
For what it's worth, I'm getting a car in a few weeks. If you want to car pool with me once I get it, that'd be great. Share gas expenses, keep emissions lower etc.
I get out pretty regularly.