Am fascinated by your question, and the fact that you are opening a rescue centre.
As far as healing goes, I would suggest that you start with the herbal route. But different herbs grow in different places. I live in the south of England, so I grow very 'traditional witchy herbs, sage, thyme etc', but my climate cannot tolerate a lot of more 'exotic' things!
I would suggest that you begin at the beginning. Start with the traditional herbal remedies of your area and research them thoroughly. Experiment with recipes, (I did, and some of them were bloody vile, and as far as I was concerned, bloody useless).
And I would also say, (and I think you've already said it!) never underestimate modern medicine. In my opinion, why drink herbal tea for a year, when a pill can remove the pain in 20 minutes...
And let's face it, modern medicine is currently taking age old herbal cures, processing them into neat little pills, and selling them!
I wish you luck with your endeavour, and feel sure that you will make all the right decisions, simply because you question yourself in the first place