I carry towels to avoid the scufs. I carried a 54" electronic rack (full box type, not just the rails) in the back of Pearl. Hatch closed. DID put a hard object behind the rack so it wouldn't slide back and trash the hatch glass! Oh, and I had a passenger as well. The guy who delivered it to me at one site in the back of his PU couldn't believe it when I closed the hatch. It barely fit in his PU! I had to take it to another site.
I have carried 10' lengths of sprinkler pipe and conduit. For lumber, I've kept it at 8'. I have carried six 2x6 or two 2x12 at a time. I've been concerned about putting a lot of weight on my center console. I have also carried very full loads of bagged garden soil. The most I've stuffed in the back is 32 cubic feet of that. I am very generous with towels on the console and on the windshield end of whatever I am carrying. I also put the material in diagonally and I can close the hatch. There isn't much traffic where I live. Half the time I go to town, I don't share the road with anyone. If I did live in a city, I'd rent a truck. But there isn't anywhere around here to do that.
I've put 20 of the 2cuft bags of mulch in the bag of a Gen-2 many times. And usually fill the passenger seat area with the other little things from that trip. Or this season it was 3 bags of fertilizer and 2 bags of seed plus some electrical stuff in a grocery bag. Prius is the best pickup you can buy.
Traffic lights? I have to drive 45 miles to get to the nearest traffic light! We don't need no stinking traffic lights.
FYI most Ive hauled is 30 cases of water. each 24 16floz bottles. picture shows 14 in the back. i didn't take a pic of the rear seat. 6 in each seat. 4 on floor behind the front seats. 2 in center on top of the cup holders.