I'm a bit of a home nudist. And I used to have tough feet and go barefoot alot when I was a kid. But in high school I ran track and cross-country and since then I have always paid particular attention to my footware and only go barefoot when I am not traveling any distance. I am still very active but I would like to be barefoot more often. Feeling the earth under and between my toes is great. Feeling the grass on your feet and what not. But... How tough can I realistically expect my feet to getconcidering how very soft they are now. 'Cause when I run I do not have the ability to constantly watch where I am stepping, my attention is elsewhere. And dammit, stubbed toes, cut feet and blisters hurt.
Put your arm in a sling for 6 months immobilizing it. Your arm muscles will weaken and atrophy. Your arm with barely have enough strength to lift itself. "How strong can I realistically expect my arm to get considering how very weak it is now?" Answer: as strong as you make it again. Details: http://www.runningbarefoot.org/
There's only one way to toughen your feet, just as there's only one way to get physically fit, and there's only one way to improve a skill - you've got to just get out there and do it - and put some practice in. You'll find it difficult at first but you'll soon acclimatise to it.