You can practice this one fairly well. I did the 50 stars achievement before I started this run and it really helped me. I got this speed run achievement the second try.
I posted a speed run video guide from Kibs (RoosterTeeth community), it has nice commentary, although some of his outdoor routes aren't very fast. But I'll post time trial guides for the route training.
You should try to get two stars on all three time trials and then this speed run should be really easy.
The first part of this level is the Burfield time trial. Kibs' route here is quite good, use that.
The final outdoor part is the Cranes One time trial. The video from UpsiloN and Skyzo covers all interesting parts.