I'm in the same position more or less. I recently discovered a book that looks to be a good "intermediate" theory text: Passive Circuit Analysis with LTSpice:

I'm in the same position more or less. I recently discovered a book that looks to be a good "intermediate" theory text: Passive Circuit Analysis with LTSpice: an Interactive Approach. Only have the kindle sample at present, as it's a fair chunk of money for my budget.