InfoPath Dev

1. Can I use the current course name and course number field to make a manual entry but also have the ability to select from a dropdown list in the same field?  Or, is it better to create separate fields?
2. In the SharePoint List where these multiple form submissions reside, what is the best way to display both an existing course name and number that was manually entered and the courses selected from the new dropdown list?  Just use separate fields?
3. If I add this new dropdown field can I then create a custom view that includes a field that combines both these course names fields but using only the one that is not blank? Not sure of how best to develop this.
4. How would I create a second course number field, tied to this new “course name” dropdown field? 
1. I want it to auto populate this new field with the courses course number when the course name was selected from the dropdown list?  
2. The course names/numbers that I need to create the dropdown list with will contain the below two columns examples. 

Course Number
ABC555003

Course Name
(ABC555003) SharePoint for Dummies

Thank you.

 Hello Zippy,

 Overall I would say that it would be easier to have the entries as separate fields, because then you can promote them in SharePoint columns, and know whether the user entered the data or picked from a list. This would be especially important if the user entered data that was not an exact match to the course/course number.  However, it may be good to have a user select from an option button or similar logic whether they would like to pick from the dropdown or create a manual entry.

For your third question, you could use the option selected to hide/show the entry to determine the value of the calculation in your subsequent view. This would be done with rules and logic, so if the selection is "manual" set the calculated field to concat(fieldchoice1, fieldchoice2).

 Here is another resource that may be helpful: http://www.infopathdev.com/forums/p/28750/98716.aspx#98716

Thanks!
Bre