How should I present myself to the US?

When entering the United States a permanent resident must present his or her green card. This establishes the prima facie right to enter the country and, as long as you have not been away from the United States for more than six months, you will be routinely allowed to return. The key is not to be absent for more than six months at a time since that is the working formula employed by U.S. Customs and Border Protection officers to determine whether you should be questioned by them about your absence. A failure to show your green card may be interpreted as an indication that you have abandoned your residence in the United States and is, therefore, not a good idea.

Unlike in Canada, where the real showdown is likely to occur on your application to renew your Maple Leaf card, the most likely time when a permanent resident is going to face difficulties in maintaining status in the U.S. is in attempts to enter. This is part of the difference in definitions of permanent residence.