What is a parsec??
Prof. Rowlett kindly answered that it is indeed based on the semimajor axis, which his pages seem to claim is known to +-30m!? Weisstein's parsec page concurs and clearly indicates parsec = ua cot 1" . So (c184) uconv(1.0*picoparsec,mi) (d184) 19.1735 mi (Note how a coefficient of single, double, or multiple precision 1.0 suppresses the big rational coefficient.) So, walkable, but maybe not for a smoker.
So you recommend Camels as the healthier alternative? The fabric discussion makes me realize that your inverse acres has a reasonable instantiation: miles/bale is the cross sectional area of the thread produced by a cotton spinning machine. How many miles is 16 tons? (There's some amount of sinkage into debt, but I was never sure how much). Hilarie