Generally speaking, why is there usually such a gap between conviction and sentencing? It just takes that much time for a judge, or are there laws governing this?

There are laws that require the Probation Department to prepare a Pre-Sentence Report (PSR), which the court relies upon to determine background facts and which issues (if any) are contested. The process of creating the PSR (including objections) usually takes 4 - 8 weeks.

Thanks. Good to know.

Once the PSR is finalized, the parties get to submit their sentencing briefs. Those briefs will include any disputed issues on the Sentencing Guidelines calculations, along with additional evidence (including testimonials) & arguments about how the Court should exercise its discretion.

What would be an educated guess