I have the non-steam version of rFactor 2 ...fairly well updated with mods and tracks. But realized recently certain mods only available on Steam - like the Stock Car 1972-1976 mod...and I've "subscribed" to it...but have no idea how to download and install it into my non-steam rf2. Any help would be greatly appreciated. And yes, I do have a Steam account and about half-a-dozen other racing games I have purchased through Steam. Thanks.
Sorry, don't think you can ... unless you find a non Steam source for the mods. Many, but not all, exist outside Steam. If you have rFactor 2 on Steam, subscribing will download and install the mod when you start the game (through Steam). You can add non Steam mods to a Steam rF2 as well, but have to do it manually.
Why the heck are you using rF2 standalone then? Do it the other way around: install it from steam, subscribe to workshop-mods you like and manually install all other mods that are not in workshop. Sounds much easyer...
You want to download Steam workshop items to a non-steam version of rF2? No, sorry this isn't gonna happen. Buy a steam copy in the sale or something.
I guess he can not update the core of the game, but he can play in single player mode or create a personal server online or a private network with versions previous to 1108 (first version updated on Steam). Possibly have more problems when the mods evolve with the more technical updates of the game DX11, etc. But it will be a matter of trying.