I realize that /questions/ask is rendered by the file ask-question.php. I have copied this to my theme's folder and customized it just fine.
The problem I have is with the sidebar. I use dynamic widgets to control what shows up in the sidebar. For the other files archive-question.php, single-question.php, etc.. the sidebar display behaves as expected i.e when I tell it to show/hide a widget for the custom post type question it does. However, /question/ask seems immutable to any settings in dynamic widgets - it is showing every widget no matter what I disable. It appears it is in "never never land" as far as dynamic widgets is concerned.