Insurance will vary from state to state, of course, but your best bet will be to get coverage with your primary carrier, if at all possible. Here in Texas, all of the carrier's will cover an older vehicle for liability and property damage with out much of a problem. They like to see you limit your driving to functions such as parades, picnics, shows, etc. and some carriers will even give you a special reduced rate if you do that.
The real issue, if there is one, comes into play when you wish to get collision coverage or comprehensive coverage. At that point they require you to have the vehicle appraised and then agree to an amount of coverage based on the appraisal. My experience with doing that has been good. I am an insurance agent and I am also an accepted "appraiser". So far, I have been able to get coverage for everyone who wants it.
One thing that they will not do is place collision or comprehensive coverage on a vintage vehicle for everyday use. And one other thing I have seen happen, if you have two drivers in your household, or three, they will not place collision or comprehensice coverage on your vintage vehicle unless you have a regular daily driver for
all of your listed drivers. I know that is the case for just about every carrier and in almost every state.