What grade would you give for this?

I would have given a B or B-. I like the amount of imagery; however, you have a great deal of cliches in it as well as contractions (both or no-no's when it comes to papers). Also, you have large words that your average reader would not understand and the letter is often wordy. There are also a few grammar errors and spacing errors, but that could have been caused by the transfer to Yahoo text box format. I agree a C seems a bit harsh, but next time try to use smaller words, less cliches, and ditch the contractions and this would certainly be an A.