We have an April 14 launch. Have been down there a ton of times, and expect there to still be decent water for that week, but it will be dropping. I expect it to be pretty freakin warm by then, great for naked evenings around the big campfire......
One item that a lot of us who have been many times have come to appreciate: a lightweight pair of long pants that resist cactus thorns. There is a ton of good hiking down there up the side canyons and even out across the hills among the saguaros. I've definitely come back from, let's just say an "altered states" hike, in shorts, with too damn many cholla and barrel cactus scrapes and spines in my legs. Found a pair of pants that were some kind of light canvas/nylon and started using them, and my legs stopped ending up like pin cushions.
So many rivers, so little time..........