I kayak and bike. If I'm kayaking solo, I will usually drop my bike off way down river, drive back to my entry point, put in, paddle to my bike, then bike back to my car.
Each type of rack has pros and cons.
Roof racks are convenient, and secure (with the right locks), but can be noisy (wind), and can damage the paint under the pads over time unless you have one mounted permanently. They also tend to be the most expensive option. The nice part about a roof system is the ability to adapt it to carry other toys.
Hitch mounted racks are strong, secure with the right locks, and not quite as expensive as roof racks, but they're pretty heavy and can block reward vision. Also, although I use this kind of rack, I'm always worried about someone rear-ending my bike(s).
Trunk racks are less expensive and are easy on/easy off, but they are less secure and can also damage your paint if debris gets under the padding.
It will come down to your wallet, how often you're going to haul your bike, and your future needs.