I did Chuckwalla one year on June 6. 100 something degrees in the afternoon. Was there for two days (Saturday/Sunday). On Sunday at 1 pm they just opened up the track (All levels, one/off as you please) because just about everyone was cooked. I made it for 30 min and I was done.
Hmmm hopefully it's not too hot for us. I've ridden Willow Springs under those temperatures and you are right the energy needed to have a good time is a bit high.
For this planned weekend I ended up buying Pirelli SuperCorsa V2's. I almost went with the SC slicks, instead I let my ego sink, and I figured I am not going to super push. In May 2010 I crashed out of turn 4 clockwise pattern. This time I am going with a bit consciousness and respect to my entry speeds.
Other than that it has been a cool starting year, so the weather may be ok. I plan in having a good time not a motogp career.
Sat was clockwise. Sun was counter. Last time I went to Chuck, they only had trailers for rent or camp out. This trip we rented a cabin and was pretty comfortable and nice. It got a bit windy Sunday afternoon but was still good. I use Dunlop slicks.
You might have the beat the heat schedule for June...