Yes, some state/districts are harder and some are easier. Lets just do some SIMPLE math. A state like California has if I am correct, 53 U.S. Representatives. The population of California is approximately 36,000,000. So, if we average it, each Representatives is representing approximately 680,000 citizens. Proportionately, that is about the same in each state. However, those 680,000 citizens could easily be located practically in one city area. In other words, a district could be about the size of a city. Being everyone, including the Representative lives in that city, they are much more easily accessible. However, you compare that with the state of Wyoming that only has 1 Representative for the entire state; and a population in the entire state of 550,000 people, and you realize that it's "Probably" easier to get a nomination in Wyoming. Wyoming is also probably easier because the 2 senators can nominate based on the 550,000 citizens. In california, they too have 2 senators, but they nominate based on a population of 36 million.
Unfortunately, that isn't the whole story. There are a lot of variables. Because wyoming is very PRO-MILITARY, Yet they are very traditional and family oriented along with the land, there aren't a lot of applicants to the academies. Even though those who DO apply are looked upon VERY HIGHLY. Last year, there were only about 19 applicants to the Air Force academy, state wide. Of those, only about half were considered "Candidates" or competitive according to the academy. Of those 9 or so, the Representative and Senators had no problem nominating any/all of them. "IF THEY DEEMED QUALIFIED". Then, being some are from military backgrounds, they were able to apply for a presidential nomination. So in that respect, it is/was much easier to get a nomination from a state like wyoming. On the contrary, you can have a district; hypothetically like Berkley California where NO ONE is really pro-military. (I don't know if they are or not, just for argument sake). In that case, maybe no one applies to the academies. You could in theory be the only one applying and have no problem getting a nomination from your Representative.
The HARDEST places to get a nomination, in my opinion, are places with a LOT OF MILITARY and a very PRO-Military community. e.g. Central Texas, Florida Gulf Coast, Virginia, etc... These are hot spots where there are millions of people who really like the military and want to see the academy and military succeed.
So, while mathematically a state like Wyoming is probably one of the easier to get an appointment from because of such a low population, there are also many other districts in the country that could still be easier because they don't have a lot of people applying.
Concerning washington state. If you live in a district close to McChord AFB (Tacoma), or a similar area very Pro-Military, then it could be harder to get a Representative nomination because they may have 30+ applicants. Whereas, hypothetically, the Seattle area may not have a lot of people applying to the air force academy, but rather more towards the navy or coast guard. later... mike...