I would install an OEM or aftermarket hitch with a cargo tray+all weather bag. You can get even get cargo trays that flip up out of the way if you don't need it once you get to your destination. Depending on what you need to carry, you might have to add a flat 4-way harness+cargo tray lights if the bag covers the tail lights and license plate.
The downside to a cargo tray is it can block the back-up camera, makes back-up sensor useless, security concern of items at night at a hotel, and the tray+bag can block back up lights at night.
The upsides are the bag and cargo tray are easy to store at home, no hit on mpgs compared to roof box/bag, no paint damage like a roof bag can do, cheaper than roof rack+carrier, easy for "shorter" people to access hitch bag than roof bag, and can use the hitch for towing or bike rack.