Legal Question in DUI Law in Washington

I always begin everything with "to my knowledge". The answer to your question: (1) I know of no prohibition with respect to visiting other US States. However (2) as for other countries, it depends. As an example: Canada considers DUI a serious offense and will not allow you across the border in most instances. There is the ability to obtain a limited visit permit, and if your DUI has been very long ago, you may be able to petition for a determination of rehabilitation. Each country will have its own rules. A simple internet search (e.g., "country name DUI entry") may provide you the information you seek.