I lived in a modular home in NE NJ in the 70's. It was the best built home I ever lived it. Since everything was factory built they seemed to use better quality materials than site built. We didn't have any issues with the home at all. It was tight, draft free with good windows.
If you have enough notice to move your machines to the second floor it should be okay. But what if the water is high enough that items lifted by your Garage Gator aren't high enough?
If you are going to put an apartment on the second floor make sure they use lots of insulation between to make it a sound barrier. Good luck - sorry it has taken this long to finally start to work on getting your own home back.