Though I can tell you that some of the jumpholes you'll find are near tradelanes. Some are behind planets, and yet others are out in the middle of nowhere.
Use the Patrol Paths function on the starmap. Whenever several patrols cluster together, more often than not there's something of interest there.
I'm not 100% on this, but I think upgrading your scanner extends the radius at which your sensors pick up objects like jumpholes, wrecks, and the like. I always thought I noticed a difference, but I don't have any actual proof. Can anyone confirm?
The NPCs go to the guard systems also, so patrol paths works. I'm not telling with scanner is the best, Igiss got mad already. Srry, Igiss!
I am a long-absent Supreme Commander, Executive Commander, Grand Admiral, Fleet Admiral, and Captain in the mighty Hellfire Legion. I have returned, and am on an urgent mission from Drake Thastus to return the Legion to its former glory, and to claim the galaxy for its own. Only then will I be able to rest.
RP Story (Still deciding whether or not to finish)
Patrol paths don't lead to guard systems. But most of them are easy to find. Just follow the map and find bases of the app. faction. Somewhere nearby there will be a jump hole (that is particularly true about pirates).
Unioners are an exception, however. Their guard entry is located in system with no Unioner bases.