Does the mall open early for walkers?

Yes

There are two doors for walkers to enter at 7 a.m. they are located on the North side by the Kid's Play Area and the entrance next to Tai Pan Trading and the new parking structure. Walkers can come Monday - Saturday. No public access on Sunday.

Mall walking is 7am Mon-Sat.

I'm not completely sure but I did notice mile markers on their walls the last time I was there so it is possible.