We almost always go in the summer, and take really long trips. We're a bit different than many on this board, in that we don't rope drop and we don't do a lot of planning. Here's how we do summer trips.
First, we either plan our day to be an "AM" day or "PM" day. If it's an AM day we'll usually show up within 30 minutes of park opening, roughly. We will set FP+ for between 9am and noon or 1pm. We hit rides with short waits in between. While we're sitting to eat lunch, we'll decide what we want to do next. Stay in the parks a few more hours, or go home. If we stay longer, it's usually only until 3pm or so. If we go home (the condo offsite that we rent), we don't make specific plans to return to the parks at night. However, if we're in the condo and decide we want to go back, we will...but most often we don't. If it's a planned PM day, we sleep in, go for a swim, just relax. Hit the parks around 3 or 4pm. Gives us plenty of time to do things...the parks are open late in the summer. Even with Epcot closing at 9pm, we still get a lot done, as the park really starts to empty around 8pm...many of the rides are straight walk ons.
Yes, the parks during the mid-day can be crowded, because I agree that most visitors don't read this board, we're a small group. However, it's still manageable if you have patience and know what rides are less crowded. Also, given that it's pretty hot, we try to do indoor rides midday and spend less time outside.
One thing we try not to do too often is PM followed by AM. It's unavoidable unless we did all PMs, but we try to limit it. Or if we do a PM, the next AM day is a bit later start. First FP+ will be 10am.