If this has been answered in a different thread, I apologise for duplication, and please direct me to the thread.
In Forza 5, I have enjoyed different types of races during the career mode - obstacle courses, autocross, track days, etc. Some of these are available in the Rivals mode, but not all, and free play mode only has two options - races and drag. In Forza 6, will there be more freedom to design the free play mode, to match the variety of races found in the careers mode?
I have no answers for you as I doubt anyone knows yet.
However I totally agree with you. The only thing that was a downer in career track days in Forza 5, along with autocross is it was one set difficulty. Increasing difficulty didn’t increase amount of cars needed to overtake in track days or decrease time for gold in autocross making these events too easy. In Forza 4 you could increase the difficulty in these events making them more replayable.
I always liked being able to pick the AI cars for online and was gutted when they took it away, but I wouldn’t mind it coming back in Free Play.
Hi! Any news about that issue?
Is free mode for all cars?
Is free mode customizable - AI cars, number of laps etc?
Is free mode for different race type?
I think about XOne but I have to know how it is. I have X360 only for Forza4… 
You can select any track and car. You can select number of laps, I believe up to 50 laps. You can select number of opponents up to 24. You can select class of opponents.
Oh. Thnx. Only class of opponents? Not car for each one?
No you cannot choose your opponent cars, just class and you cannot select multiclass except for any. I would have liked to be able to select classes like A and below or A and above but no such luck. Specific class or the ‘Any’ choice is all there is. You can try and narrow the car choices with drivetrain choices, RWD, FWD, AWD, Any but again no way to get more granular. The unusual style, bowling, timed cone gates, autocross and track days are in the Showcases section.
Check this forum thread.
Free Play options