Homecoming: Easy vs Normal

[DerSchloss]

I've played Homecoming on Easy and won (after a few attempts), but on Normal I can't get past the first three hurdles. On Easy, one is supposed to run for the bridge, but on Normal, one gets decimated. So I stand and fight and defeat the first attack and then cross the bridge with slightly diminished forces. On Normal I cover my centurians with my archers and get through the forest to the Syrians but again my forces are reduced somewhat. Then I use my archers and defeat the Parthian archers (at some cost) across the river. Then I turn and fight off the Parthian attack but suffer the loss of all my Syrian allies and a group of centurians. I quickly turn a group of archers and set the catapault accross the river by the village on fire but it takes out the group of archers before it collapses. I repair the bridge and hurry across and try to get to the forest before the Parthians on the hill attack but to no avail. I get swamped by the forces coming out of the forest and down from the hill; a pincer trap. How does one win this scenario when on Normal? This is the route I took to win on Easy; is there a different route I should take for Normal? I have found that to be the case on the two preceding scenarioes but I have tried different avenues to no avail with this one.