You can only find this free battlestar after unlocking the Track Record Loading Screen.
This is the Track Record Loading Screen for reference:
You can see the characters in the race track racing with an ATK.
On the ATK's license place you can see a battlestar, along with the coordinates: "J2 SW".
The Road Trip Week 3 hidden star location is found northeast of Wailing Woods, in the SW corner of grid J2, between the house under construction and where a small plateau ends. There is also a yellow RV nearby (though it can be destroyed by other players so look for the other landmarks.)
See screenshots and maps below to help find the location of the secret tier.
- You can only locate the secret battlestar after you have unlocked the Track Record Loading Screen.