You don't say very much about what instruments you are trying to record. Here's a thought about recording in a room leaking outside sounds. Go to a carpet store and get a large piece of thick carpet. (not industrial, the thicker the better.) The size should be about 6' x 12' Now also get some moving blankets. The carpet will allow you to roll it into a tube you can stand in and record vocals. You can also throw it over a guitar amp For drums, I would close mic and your overhead down close to the drums just in front of your face. The drums should drown out any outside noise. Other wise, use a drum machine or an electronic set with direct lines into the recording device. Record your bass direct too. Put any other instruments inside the vocal set up. That should do it. Good luck,
Rod Norman