You can do whatever you want for plumbing. PVC or that hose. What ever works best for you and that you are comfortable working with. I assume that is a RS-100 ? Depending on how many gadgets you want in the return area, running the return pump external might be something to look into as they dont give you decent space on anything below the RS-200 in the return area. For the drain to the sump, make sure you use a pvc union close to the bulkhead on the sump so you can remove the bulkhead or even remove the sump if need be.
Nice, got an RS-300 on my 90. I modified it however. The RS-200 I had on my 75 was a micro bubble mess so on the RS-300 I used 1/4" acrylic and extended the center baffle down 1" from the bottom and I also added a 3rd baffle (over baffle) You will find that at stock, if you ever decide to remove the filter sock micro bubbles will be there and the foam block is a band-aid to that problem. I can now run without the filter socks and a huge skimmer and get 0 bubbles in the display. Also reverse the bulkhead as pictured and cut chunk of 1" pvc to extend from the bulkhead to just below the water level. The sump is very loud from the cascade if you dont do this.