I got a rear basket once and it made the ECV feel like it was double the length. I took it off and it sat in the room until I returned the scooter.
I've put extra things under my legs (like something I bought to take back to the room). It is possible to set a backpack under your legs but not sure I'd drive all day like that. I wear a cross body purse that stays on all the time and put a light backpack in the basket. The basket also holds things I leave in there all day like sunscreen, extra water, etc. I usually set a half eaten thing on top when I park it to hopefully deter anyone who might look through it but there's nothing valuable in there anyway lol.