We cross there 3 or 4 times per year. Only time it is busy is related to weekend traffic by Canadians. South bound on Thur or Fri and North bound on Sun or Mon type of thing. It is a 24 hour crossing in both directions.
We've crossed there a few times. No issues at all. Can get busy at the end of the weekends in the summer as the Canadians head back. You'll be fine as long as you avoid the rush.
Fill up in Eureka before you cross as gas is a lot cheaper in the US. Also, stop at Cafรฉ Jax on main street in Eureka for a bite if you have time. It is fantastic.