I think once for the fun of it to get SDMT or something is ok. Otherwise, I wouldn't the entire trip. We had friends come stay who went in around 1-2 noon everyday from 4/8-4/12 (some busy spring break but gradually tapering off) and it made for some great nights. Others went early, petered out and didn't last to the fireworks and had to do a blitz hop day at night to catch it. They just were done at 4, saw everything they wanted (minus night stuff) and left the first night. None of this group had kids under 17, so this is just going off of adult stamina. If you go into the parks early, you start baking around 11 and it just gets worse until 3-4pm. By then, you have been at it about 8 hrs already, most in the heat. We have noticed that when we come at 1 or 2, hit something inside like Monsters or a show, (and we will have already gotten FPs of course for 4-7 p) ride a few things, then the sun sets and its so beautiful and I love HS, EP and AK at night, its the best! Its cooler, the comedians at Monsters are funnier and its a totally different experience than the stroller brigade at 10am.
Now that we have passes and live close, we just go after work at 4, even AK even though it closes at 7, and we still get our 3 guaranteed walk on FPs plus a few other things that have died down by then. I walked in and Tarzan was just hanging out, no line nothing, so I snapped a quick selfy. Evenings at the park is the best! I'd say, pick one day rope drop and plan carefully for early, Philharmagic or inside stuff. Pace yourself in the heat and you should be able to make it to the evening. Give yourself the next day by the pool, rest and eat a real breakfast, already have planned FPs towards 3-7 pm or even later, and have a splendid 12p-12a (most days) twelve hours or even later! And what's worse, don't come at 9:15am!! The bag and stroller check is murder!