It looks like the Korean War lasted a little over 3 years, or about 1127 days. M*A*S*H lasted 11 seasons and had 256 episodes.
If M*A*S*H covered the whole war, that would mean each episode would have to average covering roughly 4.40 days. To know for sure though, someone would have to go through each episode to try and figure out how much time was covered in each to really know (and some of it may have to be speculation). If I had to recall how many days each episode averaged covering, I would have guessed around 3. So, it looks like it was getting pretty close to covering every day of the war, and, if someone did go back and add it all together, they MIGHT find they covered more than the time of the war.
Maybe that’s one reason why they decided to end the show—that this would have become too obvious.
According to TV.com…
“It’s hard to believe that eleven years’ worth of stories were supposed to have taken place in the three years of the Korean War. To get around this time problem, the writers of M*A*S*H decided not to worry about it and concentrate instead on telling quality stories” (see: http://www.mash4077tv.com/mish/timeline/).
Of course, for this to work, you’d have to throw out the assumption that most people had for a series like this that there were at least some days that passed between episodes they weren’t covering, or that they weren’t trying to cover some of them because they were too mundane.
So Hawkeye wasn’t “trapped in Korea” so long it almost drove him crazy, he was trapped in a sitcom.