First let me explain: My wife has always been down to ride, for 26 years, but we're both turning 50 this year and starting to look a little silly jumping up into this old Blazer w 7" of lift on 36" tires. She's been on me for years about a step but I like my clean look as-is. I told her retractable steps would be the only way I'd do it so she said she'd buy them if I could make it work. I'm putting this out because I started thinking about this years ago and to this day I can still not find any documentation of anyone doing this. All I could find was a sweet little 9 second youtube video of a power step inserting and retracting on a K5 and that's it. The guy won't reply to any of the questions so all I knew is that it was possible.
After much research I settled on a set of power steps for a 2014 F250. Then I settled on a bracket size. Obviously you'll have to mount to the underside of the cab floor to make these things disappear so I came up with an 8"x28" and a 4"x28" -1/4" plate steel bracket with 5 gussets(In hindsight I wish I'd gone with 4.25"x28" because I could have used the extra 1/4" but I made it work). One problem is that the floor surface is uneven. This size 8x28 piece will lay flat all except for a portion of it toward the rear of the truck but I have a fix for that also. I used the two outside seat bolts for 2 of my eight(8) 3/8" fasteners/bolts. Both of the factory nuts on the underside will need to be cut off. A cut wheel did the trick. I've attached a pic of my hole layout on the mounting plate. Pay attention to how the two pieces are oriented and the notches in the edge of the 88x28 as well as the two v-shaped notches. I trimmed @5/8" off the top of the bracket and you'll need that notch or lose 1/4" of depth. I also "clocked" the motors clockwise 2 hole positions from the original locations. To do this you'll have to grind off the alignment dowel(you'll see once you open it up). I also had to cut out a square hole for the motor assembly to fit. If you use a 4.25" x28" piece instead of a 4" then you won't have to cut as much step bracket or square hole like I did.
When you put it up under the truck you'll see that the rear inside corner of the 8x24 will not touch the floor because the floor is offset up, uneven. What I do not have a picture of is the 4"x4" 3/8" plate piece I tacked on the floor side of said corner to make it right.
You will have to notch the cab frame but I don't think I've compromised anything from the looks and feel.
What I do know is that its totally unseen and works great, very solid. It may even be the end of ripping the crotch out of my old blue jeans getting into this thing.