The absence of a trained officer's observations certainly weakens the prosecutions case. However, given that this matter is more serious than a normal traffic matter, I think you would be ill advised to attempt to proceed on this matter without counsel
You ask a trickier question than you think. This is because attorneys can not help non-attorneys practice law. As such, direct instructions may get an attorney in hot water.
FYI-Reckless Driving is a criminal offense. Negligent driving in the second degree is a traffic infraction. There is a BIG difference in the possible consequences (but little difference is the basic defense strategy).
What would I do? Review the discovery materials to see if there is any chance the State can prove it's case on the evidence. If so, then I would use the court rules and rules of evidence to keep as much evidence out as possible. Then if there was still enough admissible evidence for the State to avoid dismissal of the case we would consider having a trial. Most likely this would involve cross-examining the officer and the witness and allow you to testify on your own behalf.
Thus, as you see, even if attorneys were permitted to help you, there are too many things you have to know to properly defend yourself. An attorney in the State of Washington has attended a minimum of 4 years college, 3 years law school and passed a 3 day bar exam. You have not. An experienced criminal defense attorney has handled hundreds or thousands of cases. You have not. Get legal help!!!!