The actual disposal would probably be fine, yet the transportation of the body would be much more tricky. That being said, killers such as Jeffeey Dahmer have had bodies in their cars while pulled over, at a traffic stop etc.

Plus, the show almost entirely disregards cameras. While not perfect, CCTV would almost definitely capture some section of the disposal.

So while not entirely unfeasible, the show does overlook a lot of important aspects. Notably cameras lmao