Have you measured the length of the motorhomes? A few inches over the length and you'd have a problem. As it is, 1 foot only leaves 4 inches of gap between the motorhomes and the end walls and between each other.
Also, what about the height? The height of the MH is over 10'
EDIT: A quick search of shipping container dimensions shows heights of only 9' 6" external and 8' 9" internal for a high cube container. It also shows that the size is the external size and there is a reduction of 8" on the internal size.