Using one RPI2 as a serial terminal for a second RPI2

[bob prohaska]

Is there a way to operate an RPI2  single user with the HDMI monitor
and a USB keyboard?  

Is it practical to cross-connect the UART pins and use cu on one RPI2 to 
communicate with a second? 

If not, is there a USB-to-3.3v UART adapter which
uses existing FreeBSD drivers? Amazon.com is full of cables, but most
speak only of Windows and Mac OS X. 

Thanks for reading!

bob prohaska