Took a short trip to New Era this afternoon and snapped a few pics. As Weird Al Yankovic said in the song "Amish Paradise" - "If you come to visit, you'll be bored to tears". Not much going on in New Era, used to be more of a booming area near the Willamette river, but it is now economically depressed. Mainly rural farmland along South New Era road to the east of the river. No easy access to the private land that sits between the river and the Union Pacific (I believe) railroad track and Highway 99E which runs North/South between Canby and Oregon city. Folks don't get out this way very much and when they do they are travelling along 99E to get somewhere other than New Era.
The big obstacle to getting a sub up the Willamette to New Era would be the nasty pinch-point of Willamette Falls. There are locks located here that were used more extensively in the past, but I doubt you could get anything very big past this point. Here is one page I found concerning the locks, I couldn't find any detailed information about he capacity (maximum barge size) of the locks.
http://www.hq.usace.army.mil/cepa/pubs/jan98/story10.htmping to #9316 (you had asked about it earlier).