Thanks for the inquiry!
In order to connect to your EF4500ISE, you will need to use 30A 120V, twist-lock equipment. The connection is more commonly referred to as a "L5-30" type.
In this regard, the PB31 would be my first recommendation for a power inlet box. As for the cord, you will need to find one that meets your length requirements. Consider the PC3125 as the 25' length will prove to be safe and manageable while also functional.