I'm of the opinion that the point of a mobile home/office is ultimately its function at its destination, and that any aeromods generally should not interfere with that. Many won't. And, as others have said, consider the return you'd need based on how often you'd move it.
The cost effective mods for boxes used by tractor trailers are a good place to start looking.
Side skirts (ideally that cover the wheels) and/or smooth wheel covers, rounded edges, something to fill the gap between tow vehicle and trailer (some kind of rubber or edging is useful for this), and a sloping box cavity in the rear all have good returns.
Here's a small trailer I used some years ago, with which I was able to get 60mpg towing at normal highway speeds:
The "gap filler" was a sheet of coroplast which attached by closing the trunk edge over a hook.
Subscribed! Hope to see what you make of it.