Adopt the Tomahawk and/or harpoon for land based firing they are already pretty much containerized just need a sturdy enough rolling platform ... problem solved.
geez is this really rocket science....badump dum...be here all week folks.
The ATACMS is meant to be a tactical missile system, so the range advantage of the Tomahawk doesn’t count.
And being a ballistic missile, it goes several times faster than the Harpoon and Tomahawk.
http://www.military-today.com/missiles/atacms.htm