Although I am generally not too fond of them, they do have their place, so another thing that I would consider in that application is long steps, as in 3-4' long, whatever it worked out to be with your grade, with a relatively minimum rise, say 3-6", between each level. This would provide an opportunity for someone who may not be in the best of health, or someone moving heavy furniture or appliances, to have places to pause. Either way, steps or continuous slope, I would definitely incorporate an aesthetic, yet functional and safe handrail into my plan.