Ross Enamait from rosstraining.com once inspired me by one of his videos to include ab wheel training into my workouts. I followed on of his instructional articles to build my very own ab wheels of lawnmower wheels. I started doing the rollouts on my knees, one knee, weighted on the knees and one arm rollouts from the knees.
I was ready to progress to standing ab wheel rollouts!
Ross shows standing ab wheel rollouts, progressung using a ramp in this video.
I didn't have the same opportunity as him with the walls, and the scrap wood I had wasn't strong enough to hold my weight.
Since I have a basement gym, I also store some equipment for working around the house. So I used one of the ladders in the basement to strengthen the piece of wood. The legs of the ladder is resting on the wall bars in my gym. See picture below.
I'm using a short piece of rope to secure the ladder to the wall bars. In my setup I'm girth hitching (slip knot) an eye splice at the right leg of the ladder, but you can make a slip knot of another eye knot like a bowline. On the left leg there is two half hitches. This solution is fast to set up and fast to adjust. All you have to do is retie the two half hitches.
Good luck and train hard!