If they really wanted to get 'er done, they could start by hiring competent workers and don't mean just the enumerators/door knockers, I'm talking about the out of state supervisors and regional clueless folks who have never even glanced at a map before designing field operations.
I worked the last decennial census and it was a clusterf* from the start all the way to the end and I worked five successive operations. I refer to it as the highest paying, pencil-pushing babysitting job that followed me home, moved into my house and assaulted me at all hours of the day and night.
Poor design of field ops and personnel incompetence made it far more of an ordeal than it should have been. On top of that, timing and expectations were not realistic most of the time due to logistics. It's more than the challenge of PO box use in rural areas, I lived in many areas where you had to have one because there is no delivery, even in town so the questionnaires have to be hand delivered. This time there is an online option but there isn't widespread online access, especially on the rez. Issues on the rez are another thing though I hear ads encouraging census response on the Native broadcasts and in the nearby cities' radio.
They just need more time to conduct the whole thing out here. We've a large landed state and getting from one address to the next can take up to an hour and it may tale an hour to get to the census area assigned which means it takes a while to get the work done.