Hot dog buns are still good for a week or more past the sell by or use by date as long as the hot dog buns have not begun to grow mold on them.
So as long as you check the hot dog buns for mold growth the hot dogs will still be good to eat well past the use by date.
You can freeze the hot dog buns and make them last longer but the hot dog buns may go stale tasting if frozen but as long as you use the hot dog buns within a week or two past the use by date they will be okay to eat.
I always use my hot dog buns a few days to a few weeks past the use by or sell by date and it's always been fine.
You can place the hot dog buns in a bread box or dark location to help prevent the mold growth and make the bread last longer.