But, I find I MUST get up and move every half hour or so or go 'dead'! Going out to restaurants is fun, as the getting-up process is first the 'getting-up' then a little descreet foot-stomp dance to reacquaint my feet to the earth or the like. It's not graceful, nor is it pretty?
Stairs? Did you say STAIRS? I'm not doing them anymore, unless in an emergency. Again, not graceful, etc.
Unlike many, I can still drive, but...I plan driving only when it's not bad weather nor further than 15-20 miles OR 30 minutes... longer than that and my feet go dead and I'm always afraid I mite not get back... or...dead foot hits the accelerator rather than the brake? Adventure? NOT!
As for sitting in cars? Try various pillows or cushions... adjusting these to find the rite combo can help immensely. If you aren't driving? Do various foot and leg isometric type exercises to keep the circulation going and those nerves 'awake' to any degree.
Do talk with your docs about some focussed physical therapies....to build strength [avoiding that dead feeling] and exercises you can do at HOME to build and keep up any strength you can get so you can make the most of life now.
Hope this helps! - j