I can tell you how we mounted our refrigerator, freezer, microwave and computer in our RV. if you want. the method has worked so well that we plan on using the method to secure every thing heaving on our bus conversion.
Drilled a hole thru the floor, used an eye-bolt long enough to go thru the floor (washer on each side of the floor, nylon insert nut on bottom of eye bolt– “eye” is inside, nut is outside) Did this on each side of the appliance. bought a turn buckle to hook to the eyebolt. Used an ordinary chain (we used swing set type because we have 36″ high refrigerator and 36″ high freezer.. even loaded they aren’t all that heavy). Padded the top of the appliance where the chain goes across with Non-skid shelf liner (folded over to make about 4 layers) For bus with the full-size freezer we will thread the chain thru a length of plastic hose to prevent the chain from marring the finish of the appliance. The turn buckle allows us to tighten the chain as it slowly stretches the chain. We tightened it once since we installed set up in 2006. That was in the first week. We’ve put a lot of miles on the appliances since we installed them, both interstate and primary/secondary roads. The nice thing about this set up, is we can change the size of the appliance with out worrying about feet or brackets matching up. Since our appliances are so small, we only have 1 tiedown chain looped over the top about midway between front-back. I will double for the big freezer (one towards the front, one towards the back) and also for the washer/dryer. If you do this, be careful tightening up the chain. It’s real easy to bend the appliance cabinet (a heavy “L” bracket helps prevent that).
If someone has a better way, I would love to hear it. We travel with heavy appliances in our rig and this has worked well for us, so far. Improvements are always welcome.