Hey guys, I feel like this may be the fastest way to obtain all the lap related achievements for multiplayer so I thought I would share.
Before I get into the solution, to be able to start a private lobby in Forza 7 multiplayer, you need a second player. If you have a second Xbox account and a PC running windows 10 and you bought the game digitally then you can use both devices to enter a private lobby as that is what I did. If you are unable to do that and don't have any friends playing Forza 7, then feel free to use the comments section of this solution to join up with other people.
This can be done while idle, given you have something to hold the
button in on your controller and have it plugged in. All you need to do is set your steering assist to 'Super Easy'. The game then steers for you and if you have the
pushed in, there isn't anything you need to do. Apart from wait of course.
I did this in two races with one of the IndyCars. It doesn't have to be done in the order I list them however.
-----Race 1-----
Track: Homestead Speedway Circuit
Race Length: 1h 45 mins
Max Drivers: (Doesn't matter, but I set it to 2)
Game Type: Timed Race
Track Scenario: Rain
Car Division: IndyCar
This will net you these two achievements
-----Race 2-----
Track: Daytona Intl Speedway Tri-Oval Circuit
Race Length: 50 laps (Will take roughly 32 minutes)
Max Drivers: (Doesn't matter, but I set it to 2)
Game Type: Circuit Race
Track Scenario: Night
Car Divison: IndyCar
This will net you these two achievements
Thank you to Paulfc for pointing out you will also unlock this achievement as well, completely passed over me as I did unlock this throughout the race myself.