I was wondering if anyome had any tips on how to market rental properties efficiently to buyers.

Yes, I said cost, because I'm one of those meanies who do not provide free consultations.But even if you get it for free, you would be much better off spending your time and energy on doing deals.

For me, I'd like high cash flow with opportunity of improvement and sale in 3-5 years.

We were both young doctors right out of school, with lots of energy and willingness to learn to do things ourselves - I would say most communities would pay US to move there. 

I was baffled at how your successful career was spurred by something as simple (yet difficult to commit to) as self and lifestyle improvements.

I have a buyer that would like to buy it Subject To so that he feels secures as he starts making improvements.

And the energy efficiency thing is probably worth something.

How can all of us combined be of value to the team while being as cost-efficient as possible? 

Management companies will be more efficient in the long run and (if you choose the right company) save you significant amounts of money, time, and heartache. 

In effect the property improvements are often providing a greater return than the original investment was.