1. If ATC want you to route to XYZ you route from present position direct to XYZ.
If ATC want you to route to xyz via a specific radial they will specify that.
2. An SID terminates at the last point of the SID (navaid or reporting point). This is important to know in the case of comms failure during the departure.
Some SID's have extensions known as "Transitions" that link the end of the SID with the enroute structure. In that case when cleared to the last point on the SID direct one would then follow the transition (lateral and vertical profile) unless cleared otherwise.