Ill just start with I believe its always preferred to keep yourself out of the home equation and prefer that 10 to 1.
I hope you are getting a pretty good deal on the 10 spacer as i feel they are not as desirable or trade as well as bigger stuff.
Your lot rents are low , is this market or is market like 250-300?
4000 is kind of a high number. Usually the actual move might cost 1600-2500 ( single section ) depending on what it is , distance, market etc. The other costs are utilities/skirting/stairs that get it to 4-5k.
Now that being said , can you get homes to come into your park by doing a small spiff instead of picking up the whole tab? Can you minimize cash out lay, i.e. we will give you a free year of rent to offset your move cost ( we have done this and to minimize the risk space out credit every other month..... ) .
Can you offer to pay for the move (2,000) but have the tenant pick up the tab for their skirting and deck /stairs ( just make sure the actual work gets done so it doesn't come back to bite you by looking rough.....
As randy says, there is not tremendous cashflow. In theory.... you will make it up on equity but unless you actually go to sell or refi, thats only theoretical.
Plus the $$ is going be skinny. If in fact market is 125 , lets assume 50% expense ratio at the park, via a 10 cap , each lot is worth $7500 ( again , this might be more or less than what it actually will trade at). So you will def want to keep that in the back of your head on the opportunity cost of capital for where your investments dollars will be best placed.