RTW Health Insurance for US Citizen with Pre-Existing Condition

This is my first post here on Lonely Planet's Thorn Tree Forum and am thankful for such a great tight knit community sharing all the information!

I plan on quitting my job and embarking on a RTW trip with my husband May 2015, though I am concerned about obtaining medicine en route as I don't think I will be able to carry a year's supply in my backpack with all the other stuff. It looks like there are wonderful options for those who are citizens of UK and Canada, but not so much for the US. I am wondering if I should even bother getting health insurance (COBRA, expatriate, other) as a type 2 diabetic. I am taking 2 oral medicines and insulin once nightly (Humulin NPH) and can't imagine packing my gear like a traveling pharmacy or getting stopped at customs asking why I'm carrying so much drugs.

If I don't need health insurance, where are some of the better locations to obtain medicine/treatments? If anyone has some first-hand experience about visiting clinics and refilling medicine I would love to hear from you regarding the process and costs incurred.

Our travel route: Australia, SE Asia (Indonesia, Malaysia, Singapore, Thailand, Myanmar), China, Japan, India, Jordan, Egypt, Europe (Turkey, Prague, Greece, Italy, France, Amsterdam, Spain), Morrocco, Argentina, Peru, Cuba?, and back to the US.

Questions:
1. Which health insurance plan should I look into for pre-existing should I get a insurance plan?
2. Where are some good places to obtain/refill drugs?
3. Can I just go into a clinic/doctor's office to get medicine prescribed?

Thanks in advance for your help!