There needs to be infrastructure for embarking and debarking passengers. There should be adequate air capacity to fly passengers in and out. There should be adequate shipping capacity so that there are no problems resupplying the ship. Finally, it is nice if it would be a great pre or post-cruise port.
The smallest most remote I have seen for embarkation/debarkation is Kangerlussuaq Greenland. No real infrastructure at all. I am hoping to check it out in 2014 on Silve Explorer.
On my last cruise the ship port was Bayonne ,NJ . This city has been disgusting as long as I can remember .Having a cruise port there makes no sense .I realize that it is close to Newark Airport but there should be a better port in NJ .