Mid 1600's on Prince.
I actually enjoy the Space Race. When you go for it real fast it often requires neglecting the miltary so a lot of games I end up fending off invasions as my last SS parts are coming online.
The key is tech path, getting the core cities primed for major production, and sychronizing some of the finding of techs with the construction of important wonders/components.
Great Engineers are often the key, for me, so getting to Fusion quick is a priority. That GE I often use to build Space Elevator (about 70% of it, at least).
Some games I avoid getting the Elvator and concentrate of Industrial infrastructure like Factories and Coal Plants in cities AFTER beelining to Rocketry and getting Apollo Program built ASAP.
Aluminum is vital. So too is copper, even if you have Iron, make sure copper is still coming into the Empire. I forget which SS part production is sped by it, but at least one is.
I like putting the Ironworks in a city with rivers and grassland tiles I can workshop and watermill to grab all the hammer bonuses and then run State Property. I think the Grassland ironworks seems counterintuitive, but it maximizes hammer production with State Prop civic you can easily have a base of over 40 hammers without a single mine.
Basically I concentrate on tech and economy. I avoid all the cultural techs on the top of the tree (with exception of Alpha for trading--but even that is actually not essential for a Space Ship!)