OK this is on the list over the other ones. The author basically put the thing together so that the router just fits between 2 boards, and you can zip along with that and just “mount” the ends on the boards you need for the right hieght. I really like this build. Its simple, easy, and won’t take long to do.
https://www.instructables.com/id/Planing-Sled-From-Scrap-for-Half-an-Hour/