Need to know the year? It helps with the bumper setups. But Digger Anchor might make just what you are looking for with their auger rack. Cost is around $80. I will post pics of my old school rig and maybe you can steal an idea.
If you add a big gear rack on the back, consider adding a tail light to the back of it. You can use a cheap trailer tail light and pig tail it off of the original. I’ll try and get a pic of my home-made auger rack up too.
Here us an auger carrier I pulled together a couple weeks ago. The Kolpin Rhino XL grips can be had on amazon for $21 and then just a 2×4 and U-bolts to the rail. Less than $30 and about 30 minutes to assemble.