If you are in fact a overweight 40 year old who has kids and luggage needs then what about: http://www.kickstarter.com/projects/faradaybikes/faraday-por... ?
An electric bike for hills, add on a kids seat on the handle bars and on the rear wheel and then put your groceries in the front basket. Solution. Physically incapable?
This bike is on the expensive side at $9.50/day, but compare that to car, gym membership and public transportation cost and you might be breaking even.
Of course this might not work in all locations, but it is a solution for many.