While @Marcia Maynard gives solid advice, WA has a reputation for being super tenant-friendly; whereas my experience in NH is that our courts are less inclined to tell landlords what they can and can't do with their own property, so long as the proper procedures are followed precisely and the landlord adheres fully to all applicable statutes.If the tenants are in a lease term, they can not be evicted for cause not stemming from violation of lease provisions, nor should they be; as they entered into that lease in good faith that they would have a place to live at least until the expiration of the term.

The money I have spent and the ROI is off the chart. 

Set up your chart of accounts: assets, liabilities, equity, revenue/income, expenses.

I want to know the cheapest but most precise way to find motivated sellers?

If history is any indication as Amit’s chart shown above, there’s a decent chance your TH would worth $2-$2.5M in the next 10-15 years.

Owning and operating a property management company is a huge complement to owning a real estate; owning a bookkeeping or CPA company that serves real estate investors; a construction company is another great example of a small business.Again not sure where you're heading with your question, so hard to give a precise advise. 

I am happy to forward anyone information and charts on this but Austin is use to 5-9% continuous growth.  

@Syed LateefJust google cities with highest appreciation over the last 3 or 5 years and you'll find plenty of charts

Tangental note: be sure to know the local laws and regulations on short-term rentals including any "hospitality tax" or "hotel tax" and follow those laws precisely.

I think its important to be precise in describing this because there is a big stigma to an actual eviction, and inaccurately labeling it as this could be getting off on the wrong foot with your tenants.