If you're $400 below market rate I'd give them chance to "catch up".

Assuming I also use the Airstream for lodging while traveling for personal reasons, would I just take a pro-rated amount of depreciation for the amount of use that is business vs. personal?

For them, it's truly the old-school idea of a second home. 

I'm open to properties were cap rate is around 10%+ and Return on Cash is 10%-20%. 

Hello, it is really time consuming for me to analyze each property by manually entering its data to calculate the return.  Is there any software where I can filter out properties below a certain return?  I want to be ...

I agree with William that the rate you have is probably better than you'd be able to get moving into another property with rates where they are today. 

Using a CAP rate of 7%, the $16,000 becomes= $228,000 of added value. 

My basic underwriting making some standard assumptions on HOA expenses, 20% down, 7% interest rate, 30 year mortgage, utilities, supplies, and maintenance costs shows a loss of about $22k per year if you are self managing.

Quote from @Brandon Bell: I've owned a property for four years with a standard fixed-rate mortgage, and now I'm looking to convert it into a rental.

Definitely something to clarify upfront...If you’re replacing with another restaurant, it should be an easier transition since the setup is already in place.Your biggest risk is vacancy $450K/year is solid, but if you ever need a new tenant,  ensuring the lease rate is sustainable is key!