I use Screen and a trusty USA-19HS for serial terminal emulation. Whipped up a quick TextExpander snippet to get me a new Screen, with baudrate options. Maybe you'll find it useful.
screen /dev/tty.KeySerial1 %fillpopup:name=Speed:1200:2400:4800:default=9600:14400:19200:38400:57600:115200%