For skipping on necromancer, you’d want to take a weapon set with staff and X/Warhorn, since that’s the most help you can give yourself, skipping wise.
For utilities, switch to Well of Power if you expect conditions that could impair you during your skip, if you know it’s a long skip and you can’t keep up swiftness, use signet of the locust, if you need swiftness but you’re sure it will suffice, take spectral walk. If you get swiftness from other sources, you can leave either out imo. Spectral walk also lets you completely negate falling damage if you use it shortly before hitting the ground (jump down > nearly hit the ground > spectral walk > instantly press the button again for spectral recall > falling damage has been reset > land softly on the floor, like a feather)
Other good utilities include well of darkness and the other spectral skills.
As elite I’d either suggest plague or flesh golem (flesh golem because you can technically just let him charge through enemies, giving you some breathing room), though plague is generally more applicable.
As for skipping itself… Well, sadly most ways for a necromancer to get some breathing room/swiftness include going into combat, which is really something you don’t want. You’d pretty much try to run for your life and once you get into combat, you can use your skills to keep some distance, i.e. Reaper’s Mark, Wail of Doom and whatnot. Death Shroud helps with surviving longer in case kitten happens, and so does a more defensively set up build (since you can retrait freely, make use of it!)
Also, sigils of energy are an enormous help and you should invest into them, as they will make your life as necromancer easier in general – especially when pugging.
Other than that, Necromancer is kind of kittened in dungeons, being the class that performs the worst in them. That being said, it doesn’t mean that necromancer can’t do anything; other classes just can do what’s necessary in dungeons better.
