How do you find out if there is a will as well as collect deceased father property?

My father passed last month and I was told by his live in girlfriend that there was no will. My father has a couple of vehicles which 2 of them were tied up in filing chapter 13 bankruptcy and one that he drove but his girlfriend is now driving that which I was told it was not in her name. During all of this she wanted me to sign over the vehicles to pay for his funeral as she claims but I denied because I needed to know my rights. So my question how can I find out if there is a will as well as take possession of the vehicles?