So, after a couple unsuccessful attempts (and on the first day I’ve thought of it when the driveway has been dry so the mattress would stay relatively clean), I knuckled down and got it out of the garage, carrying it somewhat precariously on my back.
As of about fifteen minutes ago, I get it out to the sidewalk and am carrying it towards the front door, and a car pulls up right next to me and somebody yells out asking if I’m OK. Yes, I say, which wasn’t a lie; this was slow and clumsy but working just fine. The voice asks where I’m carrying the mattress. Just in here, I say (the front door already being open); I’m fine. They ignore me, jump out of the car, and carry the mattress in and upstairs for me, not letting me even help. Then they introduce themselves, say they live down the street and I should call them if I ever need help, shake my hand, and are getting in their car again before I have the presence of mind to ask if I can at least give them a couple beers.
So I got a full size mattress carried up the porch steps, up the narrow stairwell, and forced around the corner through the door into the upstairs bedroom for the price of two bottles of Negra Modelo. And I met a couple of very nice neighbors!