It was nice receiving $25 each month for late fees, but the time I spent on supplies to prepare for the eviction process, e.g., The Notice to Quit, the Summons and Complaint and then having to go to court, and the filing fee's involved, etc., was costing me more in TIME (and money for forms) than the cost of a postage stamp or an envelope. 

What you described in your post is part of a bigger process which takes into account other variables such as - how long is your hold time?

It seems as if home prices are inflated due to short term low supply.

(spend 4k for the remodel and supply's)  after all the repairs the trailer should rent $400 a month.

Supply in my market is very low.

There is still the issue on cost/benefit and required ongoing costs to buy and supply salt.

Be extra careful with the sizing of the existing plant before you ever consider a conversion like this.Tankless electric heaters need  high current circuits.Tankless gas heaters need larger, higher load gas supply, chimney and venting systems.The project will not be a simple plug and play.

If you have 60 units, you can literally create your own market within your complex, and find your own supply/demand curve.  

Ultimately, it is a case of supply and demand - so I always console people by telling them if NYC wasn't so great - there wouldn't be a 1% vacancy rate and buyers/tenants would have more sway over the process.

I use it to see if an existing facility has an excess land with it, and if the area I am searching in is under supplied, I use the GIS system to find the owners of vacant land parcels in good locations for a facility.As far as how much you need to save, that all depends on the size of the facility you are buying.