Yes. Plumb it with a valve at the skimmer input and a tee above it that goes to sump. This allows you to adjust the flow through the skimmer and bleed the air through the tee'd line before it enters the skimmer. Air bubbles in the overflow can impede performance supposedly.
Are you asking about doing both things at once - gravity feed a skimmer placed outside of the sump/tank??
I ran my MRC2 Skimmer for about 3 years with it plumbed into the next room. I used a pressured rated pump - Gen X 55 - to move the water from the sump to the skimmer and then it returned via gravity to the other end of my sump. Never had an issue with it.
I will say to do this it is very important to have a waste collector attached to the skimmer so you don't have to worry about the skimmer cup overflowing.
I think I have a pic of it in one of my tank threads. LMK if this is the type of thing you are looking at doing and I will dig up whatever pics I can find