Personally, I like doing the daily tasks as I'm pretty average as a racer.
Even tho the daily tasks can only be done once a day, they still do take like two hours (more or less, heavily depends on you) to get all done, so, for me, personally, that's more than enough playtime.
You have:
- Diamond Hunt, it starts small, but, if you keep a streak, it's like winning an URL every day, it feels. I don't remember the values exactly, but, it's a pretty good income. 1200$, if I'm not mistaken?
- Magazines, they give you 800 RP and $ as a fixed value, streak or no streak. (+ 1 vinyl point every streak of 3)
- Money drops, there's 3 in each city and 2 in each countryside area. If you have good memory or keep a log or a map, you can find out where to find these and just collect everyday. All collected = 2550$ every day.
- Pursuit tasks, they give you prizes on completion and will unlock you Beamer after a certain number.
Also, have in mind that rewards for Quick Races are higher than for Custom races, so, if you can get a group to only play quick races, you might be able to get more RP and $ over time VS doing it with custom races, probably.