In future could there be a way to just have a similar "lite Install" on Steam whilst all the ISI 'Content' is available as Optional Downloads? I know this may be the way Steam does things and probably the way it's supposed to work so just wondering if anything can be done that I'm not aware of. Like making the Core of the Game the Main download and have Content as Free DLC so people grab what they want then that stays up to date after they install it.
The funny thing is, I actually started out making the Steam version a "lite install" of rFactor 2 and having all the ISI content in workshop items. When we started testing this approach, we soon got feedback that this was not giving people a good first impression of rFactor 2 as they were basically getting an "empty shell".
Our second prototype then added a mechanism that automatically subscribed people to all the ISI content in the workshop through the Launcher. When testing that, people were complaining that they had just downloaded rFactor 2 (the lite version) and now had to wait for a long time again before they could actually play it (the content is a much bigger download than the lite installer as you know).
That led us to our third prototype, which is actually what we've released now, where we used a small trick where we have a "cache" folder that contains the actual ISI content, and workshop items that users can still subscribe to and unsubscribe from that actually reference the content in this cache. This had the benefit that after the initial download, users did not have to wait any more and you could still unsubscribe from content you did not want to use. The only downside is the cache folder, which remains on disk. We considered that a fair trade-off given that harddisk space is cheap nowadays (not true for SSD disk space but you could still put rFactor 2 on a traditional harddisk).
I'm telling this story not because it's still up for discussion, but to give some insight into the thought process we followed. I hope you appreciate that.
As a practical solution, the best thing I can offer you is to buy a harddisk next to your SSD (or even a memory stick). You install all your Steam games on the SSD (for speed) and when rFactor 2 has finished installing, unsubscribe from all the workshop items you don't need so they will be uninstalled (that already frees up space) and then move the "cache" folder to your harddisk or memory stick for safe keeping. That will free up more space. The only downside is that when Steam updates the installation, it will restore the cache folder. So if you turn off automatic updates, you can prevent this from happening and when there really is an update you can copy back the "cache" folder to your SSD, run the update, and then remove the "cache" folder again. You can probably automate that. It will would require you to leave enough space for the cache folder (or you would have to move other stuff when putting back the cache folder) but at least it saves you from buying a bigger or second SSD.