So this has been happening occassionally lately - 195000 miles on eng and trans. Flushed trans a year or two back.

First time, very cold night, at startup backed down driveway and onto road, shifted into drive and car wouldnt move - increased revs and car barely moved - seemed like transmission wasnt engaged. Put in reverse moved back OK, back ito drive and it picked up and moved off. Its done this a few time over the last few months. Today 50F day I pulled over to check phone right after moving off, and when I put it back into drive I didnt move - revs went 3-4000 and it barely budged - but this time same issue in reverse - would not move inn rev either. alternate D to R and back then into D again, move off slowly with high revs, drop revs and it picks up speeed a little slowly but then is OK and it drove fine for the rest of the day.
Question is - is this portending a transmission failure and is there anything I should do to try and fix it? My ATF fluid level be a bit high if I recall.
Want to keep this thing going and get 200K on it....

 

It is likely your transmission is at it begin to fail so adjust to that and that you will not likely get to your goal.
Dropping the pan and looking at the valve body would give the best indicators as well what has accumulated on the pan magnet and settled to the bottom of the pan.
A Transmission service specialty shop can actually test the transmission pressures which would also give the information about the transmission.