Each mission was a certain distance from the others. How do their locations relate?

The missions ultimately extended over a distance of about 650 miles, from San Diego to Sonoma. There were 21 missions, so on average they were about 30 miles apart.

The more important rule / general objective the padres followed, however was to have each mission about a days journey apart. Of course the topography, the location of Indian Tribes, the availability of water – these and other factors influenced the specific location selected for each mission, so the actual distances, as you can see from looking at a map of the missions, varied significantly from the average.