Yes, people still go on hot days. Suggestion: Go during a weekday, and arrive early before the heat sets in. Then stay at the springs all day and hike out when it cools off a bit. I wouldn't recommend Bradford Ridge- too much sun exposure. A better alternative to Bowen Ranch is the new access point campground. Pass Bowen Ranch entrance for a short distance and turn left at the sign. More info on the new campground here:
http://www.deepcreekhotspringscampground.com/