I have a 2014 40G (41'4"). I tow my 24-foot box trailer around all the time. Remember a 24 foot trailer normally has additional tongue length of about 4', so that plus the receiver your total length will be over 69'. Which is longer than semis and not legal in all states, including my home state here in California.
Towing the trailer is not a problem at all on normal city streets and highways. On tight right turns make sure you go wide if turning into a single Lane. The main thing you'll have to worry about is your gas station stops, small tight gas stations are a pain to maneuver in.
Brake controller is a simple project, there's a connector underneath the steering column. You could buy freightliner adapter, but you'll still have to splice into the brake controller pigtail, so I just cut the connector off and crimped it straight to the brake controller pigtail to save the $30.