I just flew with my bike on Frontier too. Very hassle-free check in and claim, but agree that the hassle for three days, plus risk of damage is too great for three days. Usually, the seatpost and handlebars need to be removed, so getting those back to perfect could be an issue, and it takes a few hours to pad all the surfaces to make sure nothing gets damaged in shipping. I would count on long walks, or maybe see if there's a local gym that would let you hop on an exercise bike.