Relatively speaking yes. Might be one between the village and the HT - 100 miles between those - with others similarly spread out. Two ley-lines crossing are likely the most common variation.
The master of a Pop would get a special ability from the ley lines, but everyone has access to them. that's what powers all of the basic magic spells. It seems to me that deeper magic is powered by the individual and that may have something to do with why they have such dangerous effects on the mind and body as well. If the power came from a ley line, then it would be just like all the basic magics, which just seems a little less exciting and mysterious...
Not entirely true. While HM did imply there are ways to power spells from leylines, all forms of magic are present anywhere in the land. Its not mana deficient like earth once was. Deeper magic is related to the trinity of body (blood), soul (spirit) and mind (thought). Planar magics and higher magics haven't been explored much outside of chaos being potential for change.