I have a tough time imagining a situation where two years of medical supplies wouldn't be either too much or too little. Any disaster that eliminates outside medical care for two years seems likely to last quite a bit longer than that.

For this reason, it may make more sense to get a couple months worth of medical supplies and otherwise concentrate on training. Maybe you could look at an Outdoor Emergency Care or Wilderness First Responder course. They may be better-suited for longer-term care with limited resources than an EMT-B course, which assumes you have a working healthcare system to back you up.

It may be worth looking into herbal remedies, which frequently have an active ingredient that has been tested for efficacy. You do need to be careful though, since "The dose makes the poison." Homeopathic remedies, on the other hand, have consistently failed to show any effect beyond placebo in well-structured clinical trials.