Dan1,
The simple stuff:
Use a Text Object (and not a Text Input object) if you simple want user to read-only. And 'yes' you can display the VALUE of a variable there (to create this simply Right-click and select 'Insert Variable' from the menu).
Button text can also be treated in the same or similar way.
Now if that doesn't quite fit your needs, please say what you're trying to accomplish.
For example others here work to create Quizzes etc., so want to mix things up a bit. Check out this post (or search for similar):
viewtopic.php?t=3542&highlight=text+input (if you're logged in, you can download a sample pub)