For a race to go "official" it needs to attract at least 6 players (or is it 8?), so not every race that goes official will be interesting, hence: even if there is a race every two hours and even if almost all of them go "official" you will not always get a full grid, or even better two or three grids which would heighten the chances of players around you being roughly your level of expertise.
In order to play the indycar series with fixed setup and only ovals (which is kinda the beginner level and attracts rowdy teenagers at afternoons US time) as a starting point, you would need to first acquire your D licence (not done through speed but through racing safely, plenty of threads on this forum discussing how to do it quickly), then buy the car for about 12 dollars and the following tracks for 12 dollars (shorter tracks) or 15 dollars (longer tracks) for next season:
INDYCAR Series - Oval - 2017 Season 3 Fixed
Dallara DW12
Class D (4.0) --> Pro/WC (4.0)
Races every 2 hours at 15 past
Week 1 (2017-06-13) Texas Motor Speedway - Oval (Afternoon) Qual attached, Rolling start, Full
course cautions, Single file restarts.75 laps
Week 2 (2017-06-20) Kentucky Speedway - Oval (Afternoon) Qual attached, Rolling start, Full
course cautions, Single file restarts.75 laps
Week 3 (2017-06-27) The Milwaukee Mile (Afternoon) Qual attached, Rolling start, Full
course cautions, Single file restarts.75 laps
Week 4 (2017-07-04) Iowa Speedway - Oval (Afternoon) Qual attached, Rolling start, Full
course cautions, Single file restarts.110 laps
Week 5 (2017-07-11) Chicagoland Speedway (Afternoon) Qual attached, Rolling start, Full
course cautions, Single file restarts.75 laps
Week 6 (2017-07-18) Michigan International Speedway (Afternoon) Qual attached, Rolling start, Full
course cautions, Single file restarts.60 laps
Week 7 (2017-07-25) New Hampshire Motor Speedway - Oval (Late
Afternoon) Qual attached, Rolling start, Full course cautions, Single file restarts.75 laps
Week 8 (2017-08-01) Kansas Speedway - Oval (Night) Qual attached, Rolling start, Full
course cautions, Single file restarts.75 laps
Week 9 (2017-08-08) Indianapolis Motor Speedway - IndyCar Oval
(Afternoon) Qual attached, Rolling start, Full course cautions, Single file restarts.50 laps
Week 10 (2017-08-15) Pocono Raceway - Oval (Afternoon) Qual attached, Rolling start, Full
course cautions, Single file restarts.60 laps
Week 11 (2017-08-22) Gateway Motorsports Park - Oval (Afternoon) Qual attached, Rolling start, Full
course cautions, Single file restarts.85 laps
Week 12 (2017-08-29) Auto Club Speedway - Oval (Night) Qual attached, Rolling start, Full
course cautions, Single file restarts.60 laps
If you buy three to five items at one go there is a bit of a discount (10%), 6 or more items will get you a slightly better discount of 15%.
You need to finish 51% of one race in eight different weeks to qualify for "season completed" which will in turn get you a 4 dollar bonus for next season. If I were to start from scratch, i'd buy the car and the first five tracks to see if this is really what i want and then buy as many as i feel i need to buy later in the season. By looking at the schedules of seasons past, one gets a feeling for which tracks are used often and which aren't. Indianapolis for instance is ALWAYS used and attracts hordes of players (for better or worse).
I did many seasons in the indy fixed as one of the slower guys, races varied from dreadful to hugely entertaining, with three out of four being really fun, and every tenth or so being plain awful.