From all the reports of evening EMH I sure am going to miss e ride nights in the MK!
We have traveled to WDW in the summer for the past few years and the key to morning EMH is to get there before park opening! If you hesitate even a little you will find the parks start to get crowded already. By getting to the parks before they let you in the gates you are one of the first people on the rides and can get 3-4 rides done before the next wave hits. Then if you have to stand in a small line it doesn't feel so bad because you have already accomplished quite a bit.
The next key is to use fastpass if available during EMH. This helps to maximize your time.
Next you need to head to another area of the park as soon as it opens. This is really important at MK since areas of the park open a little later. If you want to see Toontown without throngs of mini people hit it first thing after it opens.
Next take in a show or two, or use a fast pass that you aquired then get the heck out of dodge! Or have a nice late breakfast/early lunch as all those people who didn't want to get up early on vacation come wandering into the park. It's kind of fun to watch their pained expressions as they see how crowded the parks have become. Meanwhile you have accomplished so much in such a short time, had few waits, the heat isn't unbearable yet, and the kids aren't cranky. As you head out to another park or back for a swim you will feel very pleased with yourself.