You have a 16 gallon hiding place right behind you.

Just make sure you remove all traces of gasoline first, otherwise it might taste funny.

You also may need to retune the engine for pure alcohol as more of it is required to maintain stoichiometric combustion.

You can also use a second fuel pump attached to a relay. The output of the fuel pump can be piped directly into the passenger compartment. You could also install a liquor tap into the dash but that may be too obvious.

You may also need to drive with a gentle foot, otherwise you'll feed the engine all the alcohol before you can hit the fuel pump button to get your own.