You know, I've been there just about every season and it is hot in summer, but its also awesome to see and it would be sad to miss. If I were you I'd go, but I'd leave the TT outside. If you can, find a place in Beatty to camp and then go in early in the morning. The road from Beatty isn't bad, there is one long downhill but its not horrid. Drive on it and stop at Furnace Creek for an early lunch. Then continue north and check out Scotties Castle and take the tour. The road out from Scotties is great, narrow but hardly any grade. Gas up out side of the park cause I've seen gas as much as 7 dollars a gallon.
If your coming down Hwy 395, just drive on by cause Hwy 109 is horrid and scary and I did it once and won't do it again.