Southwest still just charges $50 for bikes. We used a Velo II and got both our mountain bikes and two wheels in one case. We made a wheel box out of a cardboard bike box and kept it within the 62" overall dimensions limit for regular checked luggage to carry the other 2 wheels. Southwest still allows 2 regular checked bags for free.

As far as vehicles go, I don't know. Rental moving van or truck sounds like a good idea along with passenger vehicles.