Is there a general pattern between distance from Sicily and the elapsed time before a region was infected with the plague?

Yes, there is a clear pattern of expansion of the plague from Sicily to the rest of Europe.

The regions that are geographically closer to Sicily, like Italy, and the rest of Mediterranean Europe, got infected first, simply because they had closer ties to Sicily.

The rest of Europe got infected later. For example, it took 4 years for the plague to reach Germany, and 6 years to reach Northern Russia.

b.

jim crow laws were enacted in northern states.