If you have the Nod cy, you can build up a force to tie down the infantry base, or get some flame tanks to help clear the buildings. btw, the rocket squads that garrison the buildings come from out of the map, and the biggest threat are the fanatics. As long as you brought apcs, some with riflemen inside, your quite safe. If it helps, knock down the buildings near the bridge before rescuing the MCV. Watch for venoms that come from the se base, they'll damage your MCV, lose you the bonus objective. If you need credits there are credit crates south of your GDI base.