The queen mattress in my Pup kept sliding side to side. I secured it by using a couple pieces of plastic that were cut from a 5" vinyl fence post sleeve.
These are available at Home Depot or Lowes
I thought the keepers might get in the way or could damage the mattress, but so far so good.
I'd been using a stool to help my wife up the big step to get aboard. This two stepper is easier, although the installation is not a slam dunk.
The front end is a direct mount using straps. I used aluminum angle because it was handy but a heavy strap will work just as well.
You just need to drill holes in the straps at locations where the new steps mate with the bottom of the trailer bracket.
The back side will need a spacer between the bracket on the bottom of the trailer and the new steps. I used a couple pieces of scrap that happened to be the right with.
Ignore the hole and arrow - they were from another project.
The blue rectangle (bar the length of the mounting bracket) and the vertical plate next to it (same length as the blue bar) were scraps that together were the right width for the spacer. The spacer needs to be drilled to accommodate the (longer) carriage bolts.
You'll need longer carriage bolts for both sides.
There may be a double step that is an exact replacement for the single so you can avoid the additional parts, but I couldn't find one.
I needed a way to make the storage under the queen bed usable. First I tried hinging a piece of PVC pipe at the base to swing up and use a prop to keep the bed up, but it was too hard for my wife to manage.
The solution was to use a pair of gas struts which she can manage easily getting open - and the compartment stays open, but she does have to use two hands to close it.
This didn't come easy though, there was much experimenting (about 3 hours worth) and I had to send the first pair of struts back and get a 'lighter' pair.
This is the pair I ended up with from Hatchlift.com, but because they sent replacement struts I can't be sure which kit would be the correct one to order. If you have a Pup, tell them this is the strut that works and ask which kit you need to order.
Further, because I was drilling so many holes to try to get things right, I installed a plywood strip along the top of the bed frame. The bracket you see below mounted on that plywood strip is not mounted in the recommended orientation. The instructions say to mount the flat edge up, but I found this way the bed stays in the down position better.
The two empty holes to the left are the recommended place to attach the bracket (at 18" - with the pin to the bottom). I originally tried the bracket there in the proper orientation. Then, after much experimentation, found that I liked it better the way you see it now.
This place is a very convenient place for a roll of paper towels. They're never in the way, but always handy. We use the small tear offs for napkins. Just make sure you don't poke a hole in the table top when you mount the holder.