Two years ago I hiked from Bowen to the Steel Bridge at Splinter and back during the day in August in 110 degrees. But I was in excellent condition, I had 8 liters of water and drank most of it, I ate a lot of salted trail mix and I was very tired going up MOFO Hill on the way to the parking lot. My GPS registered it as 17.8 miles and 6400 feet of elevation (up and down with the dips in the middle). I was 56 YO at the time, so my advise is, yes, it is doable but the question is as stated by others are you in shape and are you carrying the needed supplies. Also, you MUST be willing to monitor your current state and to abandon your plan if you feel any issues with the heat beyond the physical effort. If you feel dizzy, unusual or start having cramps then its time to find shade, drink water and cool off, call someone to look after you. I agree with Jobe, walk out as late as you can, otherwise.