I would say any of the Cal State University schools on the list, but they are all still super impacted from years of cut classes due to budget cuts. CSUSB is super close to Mountain High and Bear, and not too far from mammoth. Sac State and Chico are nearish to Tahoe.
As for med school, you can apply from any major as long as you've completed the prereq classes (chem, ochem, bio, physics, stats, calc, and usually english, sometimes biochem and microbio depending on the school). As someone who was "stuck" in the pre-med trap, don't pursue it unless it's something you're going to go at 110%. You typically need great grades, volunteer experience, work experience, lab/research experience, and a good MCAT score to get in to medical school. You could totally turn ecology into a career if you try, "green" is still a huge growing industry that needs lots of ecologists and environmental sciences experts.