Hey Jeffrey, looking good. We did the same thing for use with a MKP hexed mat.
May I offer one suggestion....well, a couple really.
One, contour the sides. I used a dremel on low speed with a sanding drum...I just started whacking at the sides until I got a cool looking texture. Then, coat the entire hill in latex paint (just good old indoor latex paint like you would put on your walls....get a nice "earthy" color). The latex will protect the foam from getting beat you. Then, once that dries, paint a quick coat of acrylic paints in a nice earthy tone (this is where those cheaper Apple Barrel paints excel). Make a darker color wash and apply and finally....once the wash is done, dry brush with a lighter tone.
Your hills will go from being these straight edged platforms to this...
Sure, it's a lot more work....but it's well worth it