Despite their similar and sometimes confusing acronyms and their overall purpose of allowing tax-free reimbursement of various types of medical expenses, health savings accounts (HSAs) and health reimbursement arrangements (HRAs) are quite different when you get down to the details.
A full rotation of Pluto takes 6 Earth days, 9 hours, and some minutes; so the day part should be about half that amount (3 days and 5 hours), at least on average.
According to Wikipedia Pluto's minimum distance from the sun is 4.4billion km. The earth is at an average of 150 million km from the sun. Say the distance from earth to Pluto is about 4 250 000 000 000m. Not a terribly satisfactory answer (no one else has answered this yet) but I would guess about 9 years based on Voyager's current speed.