I am looking for a Post-Apocalyptic Science Fiction book

[tricky_k_1972]

I read this book in as a kid probably in the mid to late 80's.

The book was set in the US in the future after a nuclear/chem-bio war. A group of US scientists and their families ride out the underground by phase shifting. In the book they were building a ladder to the surface and each year a kid or group of kids (can't remember which) would climb the ladder and place a new rung (each rung would shift back into phase at the edges to keep the ladder stable) at the top and look to see if they see above the surface.

On the cover of the book you could see the ladder coming up to the surface and at the top was one of the kids looking out above the ground at a wheat field and a red combine with the letters CCCP on it.

The US scientists figure that somehow the Soviet Union has survived the attack and that they have now taken over the US so the they set out to investigate.

What they find is that in actuality the Soviets on the surface are defectors who rode out the attacks in either space ships or underwater (can't remember which).

Any help finding this book would be greatly appreciated, Thank You.

[tricky_k_1972]

I found it, Duende Meadow by Paul Cook.