According to RideGuru, it's about $65 for UberX -- but if you have a LOT of luggage, X might not work. Two people with normal luggage should be fine.
For availability, you might try the UZURV app. You enter your pickup point, time, location, and destination and they publish it to a lot of Uber drivers. Drivers will express interest, and then you will be able to look at their profiles to learn about them and see what kind of vehicle they drive. If one has a tiny car and another has an SUV, you can select the SUV for the same price. That way there are no surprises for either the driver or riders.
There's a small fee ($3, I think). The ride is done through the regular Uber app, so you pay normally with your credit card, are fully covered by Uber's $1 million insurance policy and your driver is an approved, background-checked driver.
If you decide to use UZURV, do the ride request the day before you need to go to Port Canaveral.