Lake temps last week were mid 60's. As far as the spawn goes, I have caught crappie up until the 1st week of June with eggs in SW Ohio.
As far as upper or lower end it's not going to matter too much. I think they may have a regatta going on down by the dam this weekend so that should take out that section of the lake completely.
I would think my main concern would be what all this rain was going to do to the lake itself. I bet it goes up at least 5 or 6 feet. There will lots of junk floating so be careful.