We were in Ca. last year and it was painful trying to tow at 55. I never tow above 65 (our STs are max 65 anyway). I usually tow at 60-65 mph and set CC at 63 or 64 by our GPS. Max. 55 just seems like you are standing still.
What happens if you do tow a trailer in the 60-65 range on secondary roads in Ca.? Are there any cops that could be lurking around on more remote roads? Will be back in Ca. again this summer and don't want to get any tickets.
Speed limits and tire ratings allowing, some like to tow at seemingly crazy speeds. I don't feel safe at above 65 mph with all that weight. I used to car race in my younger days and could easily tow faster but it's just far too risky IMO. TT brakes aren't exactly known for their extreme reliability either and when you need them the most, might not be there for you. What would happen if you had a blowout at high speed or got caught by a gust of wind? I'd rather test my driving/towing skills on roads with lots of twisty tight corners at speed (under 65).