I would love to do this myself but i have never used the editor and have no idea where to start. I was thinking a race track could be placed here... The original Hirochi Raceway track is well made and user, Insanegaz has made an additional drag expansion. I feel that this would be a grate combination as both maps are created by BeamNG them self. Thanks in advanced. Drag expansion link: https://www.beamng.com/resources/hirochi-raceway-added-drag-race-track.627/
I believe that this part of the forums is for official content, and the upcoming WCUA map will basically have what you want.
When it's ready. Actually, tdev has said atleast one more week, and it's possible it will be delayed more. He said one more week, and then at the end of that he said another week. My view is that it will come by the end of April. There is also that chance that the map won't get released in that update. We don't know when it will be released.