so i think i have it, but i could be wrong, so ill explain the process i went through.
1) worked out the number of moles of HCl, which was about .113
2) worked out the number of moles of glacial acetic acid, which was about .175
3) worked out the number of moles of H+ that would dissociate from the acetic acid at pH 4, using hasselbalch equation, got about .0259
4) used the total mole of H+ in the pH equation, replacing [H+] with (mole H+/volume) and a pH of 4, and solving for volume, giving 1387.6 L
so my guess is around 1387.6 L (i didnt used rough atomic weights since i didnt have a periodic table handy, and may have messed up other math)
in practical terms, you just put both the acids in a BIG container and dilute till it has a pH of 4.