If the garage is not built to support the weight of additional floors or is not adequately reinforced, it may not be suitable for conversion.3.

Capital investment (buying the machines and providing technology payment systems if suitable) Operating expenses (installing, servicing, collection, processing, insurance, vent cleaning, etc., etc)Term of the lease (Typically, 5, 7 or 10 years)Contingency Risk (Occupancy, market risks, competition from in unit hook up)Revenue (collections) from historical performance over the past 12 - 18 monthsCondition of the property (new construction or existing)Class of Property (A, B, C, D)In unit connectionsCompeting laundromats in the area# of MachinesVandalism risksType of Machines (front load or top load)Quality of Machines (Factory New or from Inventory)Once those variables are collected and input the commission or RENT payments can be determined universally done using a Net Present Value, Internal Rate of Return calculation along with other financial metrics. 

I highly doubt I'll be able to find anything suitable in my sub $300k budget.  

I have found that ignoring one’s instincts almost always leads to problems.Keep looking for a more suitable tenant.

Just get in touch with a local realtor who specializes in short term rentals or with on of the best short-term rental property management companies in town and they will be able to provide you with suitable properties and even give you track records of previous years so you know what to expect.

If you have a property that is suitable for a Vacation Rental, where do you advertise? 

Then they just hold your money until you find a deal that they find suitable.

You then simply inform all other applicants that unit has been rented.It's your investment, choose the tenant you believe is most suitable.

You may find IRS form W8-BEN is suitable for a foreigner doing money lending.

I'm not a licensed realtor, but I'm considering that possibility for legal reasons relating to the sharing of commissions on leads that are more suitable for a retail sale than for a rehabbing.