Average road bike total length is only about 68" according to Google, which should mean you can have the seat(s) around 7" further back than for sleeping adult(s).
My Fiat 500 was designed as "3+1": With no steering wheel or pedals on the right, that seat can be slid forward more for an adult to sit behind it. The same concept could be used if necessary for things like fully-assembled bikes or a full-size double-bass (someone else asked about that). The passenger can sit a bit more forward to leave space behind that seat.
Average road bike total length is only about 68" according to Google, which should mean you can have the seat(s) around 7" further back than for sleeping adult(s).
My Fiat 500 was designed as "3+1": With no steering wheel or pedals on the right, that seat can be slid forward more for an adult to sit behind it. The same concept could be used if necessary for things like fully-assembled bikes or a full-size double-bass (someone else asked about that). The passenger can sit a bit more forward to leave space behind that seat.