Recover from what ? If Poland is an Axis member, there is no way whatsoever the Entente would declare war to Germany in 1939. They would buy popcorn and watch the fascists and Bolsheviks tear each other out, hoping for mutual exhaustion, and if anything, deeming Hitler a lesser threat than Stalin as they had done in the 1930s.
On a more general point, both Germany and the USSR would be horrendously unprepared for their existential struggle in 1940.
Ouch, I thought this was the other thread, sorry. Disregard the part on LW. Still, they would need to prepare their ground forces. Build up infra in Poland, build up supplies on jump off points, draw up plans for attack, form up enough armored divisions, train them. Stuff like that will still probably take a year or so, no matter how you cut it. In the plus side there would be no western front to distract them. Also on the negative side no industry in France and Low Countries augmenting German industry.