A few things you should know:
1. The mailing address you put on your tax return should be the address you want the tax authorities to use in case they need to contact you. Your tax obligations are not determined by your mailing address.
2. As long as your main, primary residency (your domicile in tax terminology) is in Colorado, Colorado can tax ALL your income - regardless of where you earn it. Your domicile remains in CO until you abandon it and establish a new domicile in another state or country. You can have only one domicile at a time.
3. Other states can tax you as a non-resident on work performed within their borders. For example, if your domicile state is CO and you go to Oklahoma to do some work, the income from that work is taxable by OK as well as by CO. (In those situations CO would credit you for the taxes paid to the nonresident state.)
4. Income you might earn in other countries is of course subject to the tax laws of those countries.
5. As long as you're an American citizen, your worldwide income is subject to federal income tax.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.