Outdoor Critter Run

I have wanted to come up with a way for the little critters to have a chance to play outside.  I think the sunshine and fresh air would be great for them.  I looked at several solutions and this is what I found - an outdoor critter run:

The plan is to put this on the patio outside of critter land.  My handy dandy father in law can build some sort of threshold that connects the critter run to the opening of the sliding glass door in their room so I can open and they can access.  It has to be a super tight fit to ensure that the ferrets have no tiny holes they can wiggle through.

This giant thing was delivered in two large boxes - a bit intimidating if I do say so.  This week I am hoping to assemble and get it set where I want it so that we can measure and figure out the design for connecting it to the door.

Wish me luck....