For some time, SP 4449 and related projects of the Oregon Rail Heritage Foundation have been aware that they may asked to move out of the Brooklyn Roundhouse. They seem to have now identified their future museum site, shown at this link:
http://www.orhf.org/property/index.html

I hope they are able to take the turntable and roundhouse with them. Not sure of the date of this information, but seems to be within the last 6 months.
O. Anderson