I finished main story only. Side quests just a few.
- UFO parts, i started the mission but didn't find any.
- Documents/papers around the city, i found maybe 5, but there are a lot more
- random events, i think i did 75% or something like that
- buying buildings and business, i did half of them
- I invested in stock market, but i loose money... :-(
I had to stop to play beyond two souls (not for fun, it's a job ... :D ) after i will return to spend some more time in Los Santos.
