The collector's Edition of GTA 5 contains among other things a blueprint. It comes from none other than Trevor Philips and shows some red marks on normal light.
If you radiate the blueprints with UV light, some additional markings are visible. They are however very broadly worded, which is why I've found something in a comprehensive expedition only at a few places.
Maybe you're more lucky and can assist us with tips.
By downloading, you will receive the map in a higher resolution. It is located in a zip archive.
The zip password is: paradox.network