I want to create a game with allegro using text-based RPG elements.
I would like to describe the setting through text and give the option to input a command but at the same time display graphics above the text area.


*3 sprites, warrior, mage, archer*

(text description)

Hello, (name entered at an earlier point in the program) what sort of class would you define yourself as?
<user input here, options: Warrior, Mage, Archer>


What would be the best way to do this with allegro?

Ouch. That sounds quite hard. To the best of my knowledge, there isn't any way of combining another GUI kit with Allegro. Your best option would be to make your own text entry field. Draw out a box, and when the user clicks on it (check mouse position), a flashing bar comes up (you could leave that out). As the user types, it goes to a string which is drawn on screen (you would have a string of the input, which gets one letter appended to it at a time).
That's just an example :)