If there is no or very little snow. I made it up in August with 26 ft travel trailer to the top. It took an hour we were going very slow, no problem. With inclement weather I wouldn't go.

No. The snow pack stays in some places until late June

It might be snowy at that time of the year. I can't really say with certainty, but at 9,500 ft, there will likely still be a fair bit of snow at that elevation. All of the other reviewers, including us, were there June through September.