Building own travel trailer legality?

I have always liked traveling, and by that I mean by road because of the immense freedom to go almost absolutely anywhere on a dime and do so in an rv. One thing I have never had though is the time and money. Well I now have the time but still not the money for such an endeavor. Would like to buy a travel trailer for the adventure, but cannot afford to pay over 10 grand. My thought though was to maybe build one, possibly from a flat trailer frame, but along with that I know would come licences and legalities from dmv rules. How would I go about legally making this work.