The limit in CA is 65ft. I just attended the FMCA rally in Indio where many participants had combinations in excess of 65ft. If your not commercial you will not need to pull through weigh stations, so it would require an officer to pick you out of the crowd and measure your rig. If you speed, drive in the wrong lane, or otherwise call attention to yourself you may experience problems. But hay, you can tootle down the road puffing on a reefer, eating lunch and painting your nails without a care.
Happy Trails.