Keep in mind that none of the security you employ will deter someone who has the right tools, time, opportunity and determination from stealing your bike. The key thing is to discourage those factors. If you are locking this thing up all day every day, that's a lot of time and opportunities for someone to mess with your shit. It still can be done, but you have to be real smart about it.

If you want to bike to the train and park there while at work, I think what you probably want is a used beater bike, something that will not look so appealing to a thief. An older used bike that has some visible wear and tear will attract less criminal attention. You'll also be less sad if it does get stolen because you paid less than a new bike.

Try to lock it up somewhere that has foot traffic and open stores, somewhere that's visible. Nearby surveillance cameras are also a plus. If you are biking to 71st, somewhere along 71st Ave between Austin Street and Queens Blvd might be a good spot. Switch up where you park though, don't go to the same exact spot each time. This might just be my superstition, but I feel like if some scumbag sees your shit parked in the same place each day, they might start to get ideas about it. Avoid leaving it parked overnight.

Get a good U-lock or a chain. If you go the U-lock route, it's a good idea to get a second smaller u-lock to secure the front wheel to the frame. If you use a chain, make sure it goes through the frame and the wheels. If you go the U-lock route, be sure that your lock goes through the frame and the rear wheel. It's also a good idea to get you seat secured to your frame. You can have a bike mechanic do this for you, though it's actually pretty easy to do yourself if you have the right tools and materials. Basically you use a spare piece of bike chain, wrap it in a piece of old bike tube and loop it through the rear forks and the rails under the seat.

Unrelated to security, but something I feel like I have to say to every new city rider: Get lights. Get a bell. Get a helmet. Don't listen to music while you ride, save it for the train. You need to be aware of your surroundings, you don't need the extra distraction.

Regarding the one-way street thing, is it one of those windy roads that goes through Forest Hills Gardens? It's probably fine, but stay alert, listen for cars coming up behind you, stay visible, glance behind yourself often to keep track of where the cars are around you and to make sure the cars know that you are alert and aware of them. You might want to yield to let cars pass on these roads. That means slow down, pull to the side, look out for people about to pop out of parked cars, let the car pass, then return to a safe minimum distance from the parking lane (about four feet from their doors).