What are the implications of section 654 and 954 of the California Penal Code when the same act or course of conduct plays a significant part?

Under Penal Code sections 654 and 954, when the prosecution is or should be aware ² of more than one offense in which the 'same act or course of conduct plays a significant part,' the offenses must be prosecuted in one proceeding unless joinder is prohibited or severance permitted for good cause. (Kellett v. Superior Court, supra, 63 Cal.2d at 827, 48 Cal.Rptr. at 370, 409 P.2d at 210.) Thus, we must first determine whether the charged offenses in this case were part of one course of conduct.