Potty Training an older dog

Hello, Can anyone give me any advice on potty training an older dog, or tell me if you think it's even possible.  So far everyone thinks I'm crazy, but we just found a 16 month old boston that needs to be adopted, but he isn't potty trained...at all.  I have a weeks vacation coming up that I figured would be a good time to get him since I will be at home to take him out and what not.  But at 16 months has it gone too far...is it going to take forever? Once my vacation is over I will be working 9-4 and can sometimes go home at lunch to let him out.  He also isn't neutered - do you think that would make a difference? TIA