If your car has a factory rack or no rack at all: Use a soft vinyl roof bag. Waterproof, lightweight, easily mounted (most are secured by hooks that grip the door frames), and easy to store, roof bags are also relatively inexpensive — about $75 to $150.

If your car has a roof rack: Both Thule and Yakima sell roof-mounted cargo baskets ($100 to $360). Everything can be secured in the basket with a cargo net ($25 to $30).

If you're hauling expensive gear that needs to be locked: Thule and Yakima also offer hard-shell waterproof roof boxes, which weigh from 20 to 70 pounds and cost from $250 to $1,000.