Trying to plan a fun, solo trip in late May for a week

Background: 29M and I've never traveled alone before. I've always been terrible at planning trips, so I'm hoping you guys can help me plan a fun, solo trip in late May for a week. I'm flying out of Seattle and I'd like to keep the cost of everything as low as possible while still having a blast.<br><br>The month of May has pretty good weather in the US, so I'm leaving it completely open to wherever in the US or out of the country I should go. I'd prefer warmer weather, but I'm not picky.<br><br>I'm interested in anything that involves outdoors and/or city exploration. I would love to try some new foods.<br><br>I've already thought about the following places: <br><br>Southern Utah for the parks/zion, Arizona, Montana, New Mexico. I'd prefer to not drive for more than 4 or 5 hours. I'd prefer not to rent a car as well.<br><br>I'd like to stay under 500 for the flight. If possible, I'd like to stay under 500 for all my living costs for the week.