I would suggest you focus on any unlocks connected to toy box speedway, then start looking into anything else connected to multiplayer.
If it's soloplayer based unlocks, you can do that at your leisure anytime, as I understand it, that won't be going away.
I'm still looking for an opportunity to try a 2 player unlock of the Sugar Rush stands, it requires another player with 2 controllers to attempt.
This is my priority, as I need the unlock for two toy boxes I am working on and time is running out to get it done.
It has to be another PS4 player though, as I only play on that system./