I need door frame width, please (for purchase of fold-down steps)

[LoneStar]

I'm ready to purchase fold-down entry steps for our 2018 Montana HC.
I'm leaning toward Lippert's model because of the deep(er) step at top, but I haven't completely ruled out the Morryde model.
Our trailer is currently in storage (winter nap), away from our house; and while I could make the trip and measure, myself, I thought I'd ask, here, first:
Would someone please provide me the (inside) width of the door frame?


Thank you

Edit: I did a search before posting, above, and read where someone's was 28.25. I am unsure of this member's model, and don't know, absolutely, if they're all the same.