Hello Trollinger,
You are a lucky man to have a son to introduce to hunting and the shooting sports. Many years ago I did the same with my son and daughter and we still hunt together although they are grown adults.
Don't make the mistake many guys make when outfitting their kids or wife when they start hunting/shooting... Don't provide them with ill-fitting gear or equipment that you would NEVER use yourself... You want them to have a FANTASTIC experience... not be frustrated and not successful. I know the budget can't be busted, but this is your chance to get them start off on the right foot. Don't handicap them with junky equipment...
I started my kids off with a fixed 4x scope... They don't need a variable scope. Keep it simple and get them lots of practice from field shooting positions - Not just shooting from the bench. A 243 is perfect for the young deer hunter.
Have fun and most of all make it fun for your son - you are taking the first steps in having a hunting partner for life.
NJS