Well, what can I tell ya...first it's not the ideal subfloor for ceramic or any other tile (eg porcelain or stone) that can crack with any movement from above or below. I mean if it 'cracks', it's not a danger, just unpleasant to live with and defeats the purpose of tiling in the first place, IMO.
But the cracking will depend on many more structural issues that tiling a kitchen in a house...movement up or down of one unit relative to the other, horizontal or vertical, and if there's a solid structure there to begin with, not - say - tires...it would be a challenge...
Because even if one of the units has a solid floor and you tile on top of that, you could put an expansion joint between the 2 units that could 'flex' with the movement of each unit - but that might look funny.
You could put in a subfloor that spans the two units - but that will flex too. I am also concerned that trailors aren't meant for the added stress of tiling.
I'd look at man-made tiles, as are mentioned in other threads.