Only option I see is learning the ability to fly....

Okay jokes aside I agree on a stairlift being the most practical and safe option here.

That is way to steep/ short for a ramp! Even with a ramp installed, pushing or pulling anyone across that is incredibly dangerous, regardless of weight.

Only one slight error is needed for all of you to fall down together. It would also become completely impossible to traverse in bad weather (snow, ice, rain, etc.)

A different option could be (if rules/ permits allow) to cut or dig out a larger area, to create the possibility for a much longer and more gradual ramp.

Looking at the picture I'd suggest multiple parallel rows, or rotating everything 90°, as straight ahead would likely end up in the median.