You owe taxes to the state where you earned the income, and also to the state where you physically live. Most, maybe all, states have laws that let you claim credits for taxes paid to other states so that you're not paying double taxes by living in one state while working in another. Most states have deals with all their neighboring states so that you only have to file taxes in one. For example, I live in Michigan, and Michigan borders Ohio. Lots of people who live near the border live in one state but work in the other. So the two have a deal that anyone who lives in Michigan but works in Ohio just has to file a Michigan tax return and pay Michigan taxes, and anyone who lives in Ohio and works in Michigan just has to pay Ohio taxes. Oh, I should note that these adjacent state deals apply only to employment income, not business income. If you own a business in another state, you'll still have to file taxes in that state. You still should get tax credits in your residence state.
In general the fact that you use a server in another state doesn't make you liable for taxes in that state. I understand that New York says that if you work from home and the company headquarters is in New York, you have to pay New York taxes. Maybe there are a few other states who do this. But just because a server is in their state? I've never heard of this. If I order business supplies that are shipped from a warehouse in Arizona, that doesn't make me liable for Arizona income taxes, etc.
You are legally a "resident" of the state where you actually live. If you have a home and live in it most of the time, then you are a resident of the state where that home is. A "home" doesn't have to be a house. It could be an apartment, an RV that you live in in a trailer park, a tent, etc. If you don't own any sort of fixed home and you travel around a lot, this could be tricky.
You mentioned Oklahoma. Oklahoma defines "resident" as follows:
An Oklahoma resident is a person domiciled in this state for the entire tax year. “Domicile” is the place established as a person’s true, fixed, and permanent home. It is the place you intend to return whenever you are away (as on
vacation abroad, business assignment, educational leave or military assignment). A domicile, once established, remains until a new one is adopted.
I'm not sure that that clears things up for you.
You can't just pick a state with low taxes and claim that as your residence. No way is the state where you actually live going to accept that. If you are in an ambiguous situation, like you spend 6 months per year in state A and 6 months in state B and you have no fixed home in either -- maybe you stay at motels or live in your minivan -- you might get away with picking the state with the most favorable tax laws as your residence. But if you spend 7 months in state A and 5 months in state B, state A will almost surely claim you are a resident and owe them taxes. If you regularly wander the country, never spend more than a few days in any one place, and rarely come back to the same place twice, then you have a complicated situation and you probably need to talk to a tax lawyer.
Update - 3-4-2019
Let me correct a sloppy statement that I made above, and clarify.
You don't necessarily have just one state of residence and only have to file income taxes in that statement. In general, you have to file taxes for any state where you lived long enough to receive income in that state. If, say, you regularly travel between 4 states and spend a few months in each, then you'll have to file as a part-year resident for each of those 4 states.
You're considered a resident of a state (for at least part of the year) if you worked there to earn any income, or if you received non-wage income while living there, such as retirement benefits or profits from investments.
Yes, if you live in state A and go on vacation to state B for a week, you aren't expected to file a state B income tax return for the retirement income you received that week. I'd have to check the exact text of the laws on this. I know I've seen text like "gone for a short time and expect to return". It's possible that you could find a loop hole in the technical wording.
But if you live 6 months in state A and 6 months in state B, I would be very surprised if either state accepted that you were just in their state on "vacation" and not a part-year resident.
Ok, so what does it mean to be a "resident"? The OP says he travels around many states, so here's the definition from Missouri -- an example I used just because it happens to be the first one I found.
"The place an individual intends to be his/her permanent home; a place that he/she intends to return whenever absent. A domicile, once established, continues until the individual moves to a new location with the true intention of making his/her permanent home there. An individual can only have one domicile at a time."
I've seen similar wording for other states. Note it most definitely does not say, "A place that the taxpayer picked because it resulted in him paying the least taxes, regardless of whether he ever actually lives there." You have to actually live there on a regular basis. Other laws I've seen make clear that it doesn't have to be a house or apartment. It can be a homeless shelter, a space in a mobile home park, etc.
If you literally are constantly on the move and have no place you plan to return to, if you rarely park your RV in the same place twice, I strongly suspect that they would say that you are a resident of their state for the time that you are driving around their state.
If you really want to pursue this, you probably need to talk to a tax lawyer. If you fail to pay the taxes that the state believes you owe, that's tax fraud, and to government officials, tax fraud is worse than rape and murder.