@disk4mat @JGSchaeffer
It's possible to establish residency in a state and use it for voting, even if you're traveling elsewhere. People do it for tax purposes. My sister in law was living in a camper traveling the country and claiming South Dakota residency when she got called for jury duty, but they did accept an excuse. I imagine it varies by state, or they could just let the residents of Washington DC establish residency in the state of their choice and finally get representation.