I have looked seriously at your exact idea in Tagaytay. After much thought, my conclusions are.....1. The return on the rental (with reasonable assumptions about the number of nights rented per month, rates per night, cost of admin fees and condo dues etc.) is that the best return you can expect on the investment (assuming a cash payment for the condo) is 4% or so . To me that is not worth all the effort and risk--there are easier ways to make 4% return.
However, historically condos in Tagaytay and RP generally are going up in value by ~7-10% per year. if one believes this will continue, then the math works beautifully. The trend up has been going for 10+ years. Talk of a bubble in RP real estate values has been around for at least 10 years but just hasn't happened yet. Foreign investment (speculation??) is keeping values going. That is basically the bet you are making.
BTW, I think Tagaytay is set to continue to grow and is a really nice place. Much less crowded so far than Baguio and nice and cool.