In order to get the correct ladder, you will have to go through Thor. I just received one for our 24F. I did go right to the ladder manufacturer but they do not sell to the public, just to Thor. The ladder itself is pretty cheap but the shipping gets expensive (I paid just under $250) as it damages very easily as the ladder is a weak structure when it is not attached to the RV. If you go this route have them ship the ladder to your Thor dealer and have them decide if it was damaged in shipping...that way they will have to deal with returning it and not you. Our first ladder was damaged and our Thor dealer had to return it.