All right, I completed the Bridge and Horde Fortress with all clerics. The bridge was actually really simple, you just go north while remaining as far right as possible so that you don't aggro too many enemies while travelling to the ogres.
The Outer Horde Fortress was pretty straight forward too, I went for the strategy of not rushing for the drums, but simply holding my ground and kiting the summoned worg riders. A couple of clerics reached Level 5 around this point and I became a bit lazier since I got access to Summon Undead, which is still a bit overpowered even in the patched version. Most groups of enemies were handled by sending my summons forward with an invisible Deep Gnome to initiate combat, and once most of the enemies were focused on my summons, following up with the rest of my PCs who cast Hold Person and ranged attack.
I finished with 20198 gold. I'm not sure how the poster prior to me ended up with 60+k gold, since I only bought the Left Hand of Darkness and Short Sword of Striking. The early game is pretty sparse on decent equipment.