YEP. Replacing Suburban (or its predecessors) with Atwood is difficult sine Suburban's oblong tank's long axis is crosswise in the coach, and Atwood's is lenthwise, so you'd have to change the square Suburban cutout in the wall to make it rectangular for Atwood. Let alone actually have space inside for the different layout. Atwood to Suburban would require reducing the size of the hole, and maybe not having the depth inside for the 90* rotation of the tank axis.
I'd like to hope that the LPG connections are similar, pre-Suburban to current Suburban. Probably wishful thinking...
