My grass is TOO tall to mow!?

I am familiar with this problem. I think you can do it with your rider. Put on highest setting and the trick is to only cut 1/2 a strip at a time. Don't try to plow thru a full blade width. Will take twice as long but it works. Another option is to use a push mower. Use a lightweight one that you can maneuver easily. Once again, put it on highest setting and only mow 1/2 width strips. If it starts to bog, (either method), steer towards grass that is already cut. With the push mower, you can also kind of attack it like push in and pull back type action to keep it from bogging. You can also tip it up on back wheels and come down on the grass for an extra thick patch. When you're done, don't forget to lower your blades and go back over it again. And of course , whatever method you choose, safety first. Especially first cut. I would wear eyewear, long jeans and decent shoes, even on a rider. Ditto for every time you use a weed wacker too. Clean blades using a stick too. Welcome to yard land.