I have no troubles with your file: "Save to PDF" and "Preview" work with the same speed (about two sec). But I don't have CTB file you are using in your page setup, I used monochrome.ctb instead.

>>>The tabloid size sheet was quick to Preview
BTW, if Preview opens quickly - I mean you pick "Preview" button in Print window - than why you don't want to save PDF from Preview application? PDF is already generated and it is exactly the same as when you use "Save to PDF".

Maxim