Here's the card I did from the front, flat view. It will fit perfect in those 5.5" envelopes.
Then when you pop it open, here's the "inside of the card"
You could also write you sentiment here, but for this card, I chose to write the sentiment on the backside of the card.
Project Materials: Cardstock (Paper Temptress Flame Mica, Bazzill); Stamp (CC Designs); Die Cuts (Flip Its Square Sizzix Bigz; Spellbinders Nestabilities; Border Sizzix); Color (Copic markers); Stickers (Adorn It); Buttons (JoAnns); Twine (Doodlebug); Adhesives (Pop dots, Glue All, Glue dots);