It was said by an old man to a boy named 'X', for example, that he would be waiting for him at a kind of vehicle.
わしは天の箱舟で待っておる。 じゅんびがすんだら お前も来い。 よいな Xよ!
If it means 'good', I think it looks not make sense to me.
Does it possibly mean 'all right' and it is followed by な particle for emphasizing?