My time is limited, I want to make it count!

A few months ago, I went to the doctor because I was feeling exhausted all the time.  I am only 45 years old and should not wake up tired after 8+ hours of sleep!  After an EKG, a very observant nurse practitioner noticed what they call a left branch bundle block.  She had a background as a cardiology nurse, so my first thought was "of course she's going to think its heart related, that's what she knows!"  Thank god she did because this had been missed by a doctor 2 1/2 years ago on the exact same test with the exact same results!  Had it been caught then, my condition would have been treated in the early stages and my current situation would most likely be very different.  Instead, the damage was allowed to worsen over the years and has now progressed to Severe Cardiomyopathy with my heart working at only 5-15% of its capacity, normal range being 60-70%.   With no treatment, life expectancy would be less than 1 year.  There is no cure for my particular type of cardiomyopathy and no exact known cause for it, with heredity being the doctors best guess.  My parents both died around the age of 40, so my family's medical history is rather limited and life longevity is not exactly in my favor.  Treatment with medication, I am told by a few cardiologists, goes by what they called "the rule of 3's" where typically 33% get better, which, at best would extend my life a few years, 33% remain the same and  33% get worse.   I have translated to mean they have no idea what is going to happen and like I mentioned earlier, if it stays the same or worsens, my life expectancy would be a year or less. 
Facing your own mortality is a curious thing.  Everyone knows they're going to die someday but when you're given a small time frame, I think how you handle it and what you do with that time, defines you as a person.  I want my definition to be a good one! 
So, basically, I am at a point where I have to make a choice, go back to working 60-80 hrs/wk, knowing my time on this planet is limited which would be an exercise in futility or map out a plan for the next few years to get as much out of life as possible.  I choose the latter.  If I had a wife and kids, the plan would be a no-brainer, I would want to spend as much time as possible with them.  I don't have that so, instead, I want to travel the world experiencing everything this planet has to offer!  I would like to make a difference, however small, wherever I go on earth.  Unfortunately, this is not free, which is why I'm here.  I recently hooked up with a worldwide volunteering organization. I want to spend the majority of the short time I have left in this life helping other people.  To be honest, this decision is far from selfless.  Am  I volunteering to see the world?  To help with travel costs?  To make a difference?  To chalk up karma points?  For personal fulfillment?  YES! 
Along with money, I need ideas on what to do.  What is the one thing you want to do before you die?  Those are the things I want to do!!  If you choose to donate, know that it is needed, appreciated and it will be put to great use! Thank you so much!