I have a home that is an STR in a highly desirable tourist destination.

It was highly recommended on a BP thread many years ago.I don't do subject-to's, but just be careful. 

I am looking for an appreciation and to cover most of my mortgage.Also any tips how much such reno could cost are highly appreciated.thank you

There are several reasons for that including but not limited to, landlord friendliness, lower prices, population growth projection, positive job growth rates, lower crime rates, 1% rule, to name a few.

This can get complicated if you are racing against time between getting it sold versus the banks take over.Can you get it sold at a high enough price to pay off the mortgage or is the owner under water?

I have a home that is an STR in a highly desirable tourist destination.  

Clair-Mel: This area offers affordable investment opportunities with high rental demand potential.

Replies are highly thanked. 

My wife and both make a high income for our area and I feel we could save about $100K per year to keep buying. 

Let's assume you did put a high down payment, on a refinance lenders will cap you at 80% of the new appraised value, leaving you with little to no money on a cash out refinance.