Vacation Rental Valuation??

[Jon Moser]

Hello BiggerPockets! I am very new to real estate investing and need help putting value to a property that I have come across. The property has 3 log cabins that sit on 5 acres of land. All built with in the last 20 years and are in great shape. There is also a plot with a 50' x 70' metal building and a well that supplies the cabins. The couple runs a very successful vacation rental with these cabins. This property is not on the market, I approached the owner after learning they want to sell in the near future.  We have had a number of conversation and we have gotten to the point of talking price. Being that it is not actually on the market I have no clue what their asking price will be or should be. After talking with the owner, he wants me to shoot him a price. The only numbers that I have are the assessed value from the county assessor. I also know their approximate yearly income from the rentals. How do I value this type of property? Any help will be greatly appreciated!