Alright, so I will answer my own question for transparency! This is using existing forum posts about converting tracks from rF1 to AMS for personal use already on RD e.g.
https://www.racedepartment.com/threads/conversion-tips-for-ams.118466/
1) Download VirtuaLM Mid-Ohio for rFactor 1:
2) Download rfactortools:
https://www.racedepartment.com/downloads/rfactortools.1954/
3) Extract them both into Downloads (or wherever you want)
4) Create an empty folder to contain the AMS conversion you will do ( I called mine "henlo" for no reason)
5) Open rfactortools-gui
6) Select the extracted rF1 track directory under Input, and your newly created directory from Step 4 under Output
7) Select the checkboxes in the screenshot below (note that some rF1 tracks require "Fix Light Intensity", but Mid-Ohio seems not to)
8) Be sure "Track Filter Properties" contains StockV8 * (as in the picture) to allow all cars to use the track (and if left blank, the track will not show up in-game)
9) Click "Convert"
10) Look in the directory from Step 4, and you'll see a GameData folder, which you should just copy into your AMS install folder as per usual with mods!
This of course does not add any AMS features or anything -- the track is exactly as it was in rF1. But for tracks of a high quality like this one, it's not so bad!
An important note: if you dig around the forums here, you'll see people mentioning that you need to change a few lines in SCN files for conversion to AMS -- but this does not apply to conversions from rF1. You literally only need to do what's above, nothing more, and it "just works" for rF1 tracks. The line changing thingamadoodles ONLY apply to conversions from GSCE, and even then, it varies a bit from case to case, it seems.
