You don't necessarily need to start with planet scale terraforming let alone planet orbit modification. Large scale space habitats (like the Oneil island 3 cyl

You don't necessarily need to start with planet scale terraforming let alone planet orbit modification. Large scale space habitats (like the Oneil island 3 cylinder) are possible with 1980s technology. And if you really want to use planetary bodies then incremental covering its surface with a worldhouse is much more cost effective than a full scale terraformation where you need to invest huge resources for hundreds of years to only get the benefit at the very end of the whole project.