s Both the Soviet Union and the Nazis took a keen, ideological interest in the production-side innovations of "Fordism," but to my knowledge only the Nazis parroted Henry Ford's statements on the benefits of automobility and made any attempt to promote mass automobile ownership. Why didn't the Soviet Union develop any program similar to the KdF-wagen (Volkswagen)?
For those who did own cars, what was there to do? Were long automobile vacations possible? What automobile service industry existed - gas stations? mechanic garages? drive-thru restaurants?
Soviet citizens were simply too poor before the war, and for a time after the war. GDP per capita was roughly a third that of Germany's on the eve of war (I say roughly because GDP numbers can vary a lot depending on the source). Even in Germany the cheapest foreign models were considered just out of reach for the great masses. Hence the Volkswagen, with the goal of costing some 2/3 of the cheapest locally manufactured American models.
An additional problem for the Soviet Union was the backwardness of it's industrial sector in the 1920s (exacerbated by brain drain as highly educated people left after the revolution). Vehicle manufacture was very limited until capacity was greatly increased in the 1930s by having foreign companies build plants for Soviet industries and train local engineers to run them (Henry Ford played a very prominent role in this effort). Motor vehicle production rose from a mere 800 in 1928 to 200,000 in 1937. The deficit of vehicles meant the military, business and farming sectors were given priority. The transport needs of common people were served by expanding mass transit.
Why didn't the Soviet Union develop any program similar to the KdF-wagen (Volkswagen)?
KIM-10 car. Developed since 1938, first cars (prototypes) in april 1940, stopped in june 1941 due to war. Factory ("Moskovskiy avtozavod imeni KIM") was reconstructed in 1939-1940 to be able to produce 50000 cars per year. ( http://auto-junior.info/istoriya/azlk/istoriya-sozdaniya-i-stanovleniya-azlk-mzma/ , russian)
[Unverified] It was planned that 10% of Soviet families will own KIM at the end of third Five-Year (1942), and about 80% of families at the end of forth Five-Year (1947). Unrealistic, but kinda typical for those years plans.
Were long automobile vacations possible?
Yes. At least in 1980s.
gas stations?
Yes, AZS (Avtozapravochnaya stantsiya)
mechanic garages?
Yes, STO (Stantsiya tehnicheskogo obsluzhivaniya), though cars were mostly repaired by owners. Also it was difficult (in late 80s at least) to get replacement parts.
drive-thru restaurants?
Can't tell for sure, but don't remember any.