Many states have a max allowable length of 65' and with this law there generally is no reciprocal privileges. That's mean if you're legal in your own state, you won't be legal in a state that has the 65' limit. Sounds like you may be right at 65' so you should be okay.
Now having said that, I have seen many motorhome trailer combinations on the streets here in California that are clearly longer than 65' yet I've never heard of anybody getting a ticket for it. Doesn't mean it still isn't illegal, it's just one of those laws that doesn't get a lot of enforcement when it comes to RV's.