Some addition thought toto your scenario:
Fact: Bolkhovitinov DB-A aircraft that attempted to fly non-stop from Moscow to Fairbanks, Alaska in August 1937. It disappeared near Alaska and was not located at the time, despite an extensive search for it and its crew.
Fact: The DB-A first flew in 1935,
Scenario: What about in your scenario, these DB-A flights from Moscow to Fairbanks in Alaska, although openly promoted as a means of Soviet Union’s international prestige, are in fact covert mission profile flights to establish and test navigational routes and strategic photographic reconn for the coming invasion?
Fact: Based on preliminary calculations, if all of the weaponry was removed [from DB-A], then the weight of the empty aircraft would be 16 tons. In order to ensure a range of at least 8,000 kilometers, the aircraft would have to hold 16.5 tons of gasoline and 900 kilograms of oil.The crew, along with equipment and food supplies, would add up to 1.5 tons plus a minimum of miscellaneous baggage—in total, we had already exceeded 35 tons for the takeoff weight.
Fact: Two long-range aircraft made it from the Soviet Union to the USA, both Tupolev ANT-25's.
Fact: On 20 June 1936, in a modified ANT-25, a crew comprised of Chkalov, Baydukov, and Belyakov executed a 9,734-kilometer flight over the north of the Soviet Union in a time of 56 hours and 20 minutes.
Fact: On 18 June 1937, the transpolar flight of Chkalov, Baydukov, and Belyakov began. Sixty-three hours and 25 minutes later, the ANT-25 landed in the United States at Pearson Field near the city of Vancouver, Washington.This flight opened the shortest route over the Arctic ice from the USSR to the United States.
Fact:Tupolev ANT-36 - a bomber derivative of ANT-25!
Sources
http://bayourenaissanceman.blogspot.com.au/2013/10/has-missing-pre-ww2-soviet-bomber-been.html?m=1
https://www.warbirdsforum.com/topic/1201-got-the-bolkhovitinov-db-a/
Regards
Pioneer