It is very easy to get up faction in Rivervale..

1. Stop killing Mangler.. the only way he attacks you is if you go in the
back room of Kevlin Diggs shop (which you don't need to unless you're a
rogue trying to complete a quest). If Mangler does attack you zone out so
you don't take the faction hit.

2. Not sure what lvl you are, but kill Mooto if you can. He gives great
faction.

3. Continue to hand in RE warbeads and orc centurion belts.

4. After Misty thicket stops giving you exp, head over to Beholder's Maze.
It gives good exp and it still raises the same factions as Misty. Same
goes with Runnyeye once Beholder gets too easy for ya.

BTW.. you don't have to buy your spells from Rivervale.. go somewhere else
if it's a must.