First off, you are not required to allow them to enter your home. Secondly, remember the census is just that - a head count of how many live at your home, so there's no need to provide more information than that. However, the Census bureau seems to think they have the right to ask you for additional information, which I believe is unconstitutional.
You can find this out for yourself on the Census Bureau's site, which indicates they may ask you for the following additional information:
- Your household finances
- What you purchase
- If you're employed and by whom, and how you commute to work
As for me, I'll only be providing the total number in my household such as 1 stuffed dog, a cherub on a lamp, and a cement lady statue - lol. In other words, knowing my rights I'll be applying common census sense! What about you?