Expect some snow way up top, but the road should be walkable. Your main issue will be how far up the road you can drive. It gets steep and rough at about 7,200 feet. Assuming you park around there, you're looking at 9 miles r/t, 3,000+ ft of gain, so it's not too bad. It may not get bladed early in the season, so rocks and some deadfall may be an issue.
I went in July, with temps at the base around 100 degrees during the day. I parked at around 7,200 feet. However, I started walking at 0-dark-30, which meant I summitted at around 6:30 am and was down before 10. It was toasty as I returned to my truck. It's a beautiful place. I hope you have a lot of fun!