Considering a single level ranch house with a full hip truss roof and large overhangs. How does one gain access to blow in ceiling insulation without using pull down attic stairs ?

either through the attached garage, or through the insulated, weatherstripped attic hatch that you need to install anyway (it's a code issue) for emergency access.

As Bob I said except locate it in a closet ceiling, like they did in the old days.

Yep, you need to provide a code approved opening(certain dimensions to fit between common roof truss spacing). With a hip truss roof, about your only option are those mentioned above. With a gabled truss roof, the access can be outside thru an opening in a gable end...