speed rpms

Hi guys, I was curious about using my Grom to commute to my second business which is a bit out of town. I'm a small guy 5'6 115 pounds. There's a small stretch oh hwy that's 100 km (60 mph) I was wondering what is the longest I could keep my Grom almost full throttle? I've maxed out around...

Whats top speed or rpm u could run at for a couple hours?