ocshooter

Hi, I've had my GMRS license for a while but haven't bothered using it since I didn't think I was in range of a repeater and LOS wouldn't help me. Well, I found a repeater in my county and want to see if I can hit it, so some basic questions if I may: Are all GMRS repeaters simplex, or do I need an input and output (uplink/downlink) setting? The repeater in question states that the National Travel Tone is active...what does that mean and what is the tone freq/is it a common freq? What settings would I enter in my Baofeng, if simplex or duplex and if a tone is needed? If I'm hitting a repeater will I hear it opening when I key the mic? Thanks in advance!