I purchased a few off ebay.
The Evans 4-car auto loaders (including the LCCA 2014 auto loader 6-58584) by Lionel do not fit Menards Sweptsides on the bottom row. They (the Sweptsides) are too tall for the end ledge by a fraction of an inch--they would fit if i took the tires off, or bent that lip down, but I don't want to do that.
The Menards Dodge Power Wagons are too wide for the lower level.
Plymouth Furys fit perfectly.
I think that Ford Panel Vans also fit perfectly, but I do not recall.
I then purchased a truckless and car-less 4-car MTH auto loader (with 8 chocks and rubber bands). This fits all Menards 1:44 $5 Denver Die Cast cars & trucks very well indeed on both the top and bottom levels.