I would definitely go measure the property, or worst case if you are that lazy wait for spring to come around and tell them to let you cut it once so you can figure out your price. If this is your friend that could be an option. I did the second of those options once whit the largest property I Currently have (3 acres). I gave him a ballpark figure but asked him if he wouldnt mind me cutting it first to get my time down as I had never done such a property before. He gladly agreed.