George,
A few years back, I toured several motorhome factories in Oregon. The one that was producing Beavers (at that time). I stopped and spoke with a production individual about tile adhesive/grout systems and what they used, and he said that they had a lot of problems with cracking tile and grout. They had replaced the whole system with new adhesives and grout specifically designed for RV installations and other installation cases needing to flex without cracking.
You could call Monaco, and see if they would share the product names that they use now. Beyond that you may talk with the application engineers of the tile grout and adhesive manufacturers. I'm sure you want adhesives that flex and offer some movement and the grouts will probably use more latex additive in the system than is needed in home installs.
Any underlayment fastener that works itself up in time under a tile, can crack a tile, so being sure those are recessed and secure. Hope this helps.
Later Ed