Roofing solutions are not an inexpensive choice for homeowners. Make sure the money you do spend is spent wisely and you don't put yourself in a position of throwing good money after bad.
You say re-deck, prime and roll roof. What type or what MFG are you considering? GAF (Liberty) Certainteed (Flintlastic) ABC (Mule Hide) are some excellent systems IF applied correctly. They are peel and stick and you don't roll out bonding agents like we you to with some older materials. Less fumes and room for error. What ever you do, stay away from 90# roll goods glued down.