I have a mod with an improved skyranger that has side doors, but unfortunately it does not have ladders. Creating and editing maps is not something I can do but I know Hobbes has a ladder in some of his maps, that work like the grav-lifts in UFOs. It should be possible to grab it from there and use it (if it has the correct orientation).
I've attached my craft mod, any ways and with a bit of help from Hobbes you can get a ladder in there too!