Hey Brandi,
My husband and I went to the big Island for the solar eclipse, back in '91 (I think). We did a tour around the Island, so we wanted our own bikes. You can rent, but since you have friends who you can ship your bikes to, I'd recommend that if you're comfortable with putting them back together. Besides the comfort of having a bike you know fits, it's pretty cool to have pictures of you on your own bike in a new place.
Have fun. I'm jealous!
"Bicycling is a big part of the future. It has to be. There's something wrong with a society that drives a car to workout in a gym." -- Bill Nye