I personally would not tackle the skimmer even though I consider myself a handyman.
The sump on the other hand is merely a container that usually sits below the tank. It provides several benefits;
1 Adds extra volume to your tank ( bigger the better).
2 Place for you to put your stuff in (return pump,protein skimmer,refugium etc).
3 Easier to do partial water changes.
4 can "medicate" your tank from the sump preventing any shock to the critters.
Mine is very simple I bought a 16gal rectangular storage bin which fits nicely under my corner tank. I also addeda smaller bucket inside of the sump which i now my refugium. HTH