The game does OK in most situations. Midway was not a submarine base until after the Battle of Midway. However, it was a fueling location for any type of vehicle that it had fuel for, and the subs did stop by on their way out, and usually on their way back. Most of the time, they would run at Ahead Standard, which was close to a "best efficient" speed. You did not want to be wasting Uncle Sams fuel reserves, especially if you were going thousands of miles from the nearest fueling location. Ahead Full and Flank were used (usually) only to attempt to close a target. The stock game does fine at all of that. It's only problem is giving you "Hollywood" or suicide missions, such as photographing ships near Nagasaki, or similar.
The "traveling" aspect for the US submariners was somewhat restrictive. Initially, they were basically ordered to be submerged during daylight hours, and when within 500nm of any Japanese air facility. But when they came back from patrol, were criticized for having been submerged too much. Also, their pre-war training taught them to not be seen by any one at any time, and that sonar targeting was the way to shoot their torpedoes... Add to that, the fact that the magnetic pistol used on the torpedoes was faulty, and pre-mature detonated quite often, and you had a recipe for reports of lots of sinkings, but not actual "witness" to same. What would happen, is they would "target" a ship via sonar, shoot their torpedo, which would then premature detonate, and the skipper would naturally think he had a "hit"... Anyway, there is much more to the story. The best book that I have used thus far has been the old reliable "
Silent Victory" (that is a SubSim related link) - not that you have to buy that book, much less buy it from Amazon or through SubSim, but that is the best title I have found, if you are wanting some background on the "who, what, when, where, why and how" of the story. Have fun with it! When you get into modding, I do recommend
Fall of the Rising Sun, but for now, do Stock and get used to the game. For a first mega mod, especially if you like the Stock game is to use THEBERBSTER's
THEBERBSTEES All In One Beginners Mega Mod List For SH4, which is a re-working of Webster's
Game Fixes Only. Highly recommended stuff. Of course, I could bombard you with about another dozen mod recommendations, but I'll leave ye be for now...
You'll have to forgive my manners - I almost forgot: "Welcome to SubSim!"