Do rattlesnakes normally mate close to where they live?

Yesterday at about 3pm I walked into my backyard to do some work and I heard a commotion in the gr.I looked over to find 2 rattlers, mating! I ran it the house and watched them through the top portion of the dutch door.They were both between 3 and a half and 4 feet long. I nervously called my BF and he said "watch them, make sure they don't go under the house"ok, well-I agreed to this not knowing that this mating ritual can take quite a while.So, time pes and I think they are done-but they are slightly out of my site being behind a tree trunk.I went pee, and came back to find them about 10 ft apart.One was headed down the canyon.The other was pointed towards the house but slightly towards the same direction the other one went. The phone rang and I went inside to answer it. I came back and I couldn't find the one pointed towards the house. 1) how close do they normally live to where they mate and 2) approximately how old were these guys? PS - these are northern pacific rattlers