Since you are flagpoling you will probably not have anything other than documents, like you said. The goods list will be for the stuff that will follow you later as part of your immigration, which in reality means you can make a list of things that you want to bring as a settler (within one year of PR I believe) and pay no taxes on it. It can include jewelry, vehicle(s), and whatever else you want to bring.
No one will stop you before you reach this address. When you are closer to the destination though, you will see signs for U.S. Border/Customs, just follow the signs and the cars which will get you to the officer. If you haven't crossed a land border before, it is exactly like a toll-booth where you will stop and handover your passport and show your intention to flagpole (the officer may not know what that means and would try to find a visa), you have to tell them that you are turning around to re-enter Canada. This will most probably keep your passport and escort your car to the immigration office where you would have to park and go inside to do the volunteer non-entry process. At the end of the process, they will give you a letter which you will show at the Canadian border when you come in. The Canadian border officer is interested in knowing where you are coming from and to that you will tell that you have only flagpoled from the U.S. border and here is proof of it.
Pretty straightforward. Good luck, and feel free to ask should you have any other questions.