So we're going to Chicago in a couple days. While we're there FI's family is throwing us a couple's shower. We've put together out-of-town packets for all our guests. It's just tourist information from the Tampa CoC. Anyway we want to write a letter to all the guests to include with the packets. Unfortunately I have never seen anything like this done, so I have NO idea where to go. I can say 'Dear Guests', right? We mostly just want to include info on the room blocks, flight discount & website. Can I style it the same way I style my mass emails to guests? They're usually light hearted and full of jokes. Would the letter have to be more 'professional' or 'etiquette-y'? Thanks for your help ladies!