One was that there was a significant cost to make the units ADA compliant because I would have to make doorways and bathrooms larger for wheel chairs and the other was I tried to contact the list of agencies provided with the course and I hit a dead end on that after sending letters written exactly like a template provided with the course and I never received one response.

This is my new wheelchair accessible bathroom, with a roll in shower.

You can't charge anything, anywhere in the United States.You have to treat it like a wheelchair.

You could go overboard and put in ADA wheelchair width front door and bathroom door If you wanted to dedicate this unit long term to elderly customers.Just my 2 cents. 

In my earlier response, I did not intend to imply there is any reason to eschew stacked duplexes, triplexes - we have a couple and, as @Matt Geerts points out, no stairs on the ground level provides the opportunity to create an accessible unit for those in wheelchairs or other mobility issues {Matt, might consider this ... designing with wider hallways and doorways (36/38") and a more open bathroom layout (perhaps with walk/roll-in shower) is simple when building new or doing a major renovation.} and makes your unit appealing to new categories of tenants (those with disability and aging Boomers are but two).That said, when looking at an older residential building {i.e. without an elevator}, my preference is still for side-by-side units over stacked.

Even if he was 90 years old, sitting in a wheelchair, and covered in war medals.

I don't care if he's 90 years old, in a wheelchair, and covered in war medals.

Each one is handicap/wheelchair accessible.

Yes, I've had some luck and some results from effort.The best luck came when the main dealer who operated out of a wheelchair had a pretty severe medical issue and was taken away by ambulance and hasn't been back or any of his other cronies.

It will cost me approximately $24,000 to modify to approach barrier free ( 36 inch door ways and wheel chair accessible bath ) for a 3 bedroom ranch in northwest Pennsylvania.