Have the property delivery vacant. 

In that instance you can offer to buy and arrange delivery of the materials yourself. 

They use Ashley furniture, and do weekly rentals with free delivery and pick up. 

Three weeks ago, I told the tenants about the delivery.

Just like Amazon created the two-hour delivery, Elon is looking to figure out a way to return any Californians we don't want with a "hyper" return policy, haha!

That's where a good delivery can turn into a poor final product.

If I change the 2nd line to "2nd payment - 25% after rough inspections PASSED and purchase and delivery of all (or majority) of materials completed," should this contractor leave again, at least I'd have the materials in hand to protect myself...

When moving the mobile homes unless the seller is paying for the delivery cost you will have $3-5,000 in moving cost, if these are new sits you will need a foundation or piers to put them on $2-3,000 in piers setup and pour, and then setup and install you will have a HUD installer who can do block, level tie down, water/sewer (need a well at the location and septic system if not already at location), gas/heat hookup this will cost $2.5-$3,500, electrical hookup which can be $500- $5,000 depending if there is current service there or not and then skirting around $1 - $1,500.

@Tanner PileI agree with Eric's answers, but the delivery will be equally important since you are sharing a space with this person and do not want to start off on the wrong foot.

With online shopping, Amazon Prime delivery, etc., there is a continuing decline in demand for retail space.