We've been using a Saris Bones 2-Bike rack for our two bikes. I found out about it on
https://www.bikertricks.com/ and I'm glad that I chose a hitch-mounted one as it is easy to install when I need it, and easy to take off when I don't. This makes it ideal both, for long and short trips. Because the rack is installed behind the car and not on top, it's very easy to load and unload the bikes.