The most important thing for you to decide is, do you wanna spend most of your rounds casting spells or swinging your sword?

For the former, as MoG said, pretty much every lvl before 5 is a good stoop, I'd only take lvl 4 if I'm hurting for an ASI right now, otherwise stay at 2 or 3.

For the latter, Ftr 11/Sorc9 or Ftr 12/Sorc8 are solid.