Retractable tonneau covers are a very popular solution for protecting the truck bed. Retractable truck bed covers typically feature a canister at the bulkhead of the truck that the cover retracts and rolls up into when the bed cover is opened. Retractable tonneau covers are known for being very low profile, easy to use, and great for 5th wheel towing. Most are mounted with clamps and rails and do not require any drilling.
If you're shopping for a retractable truck bed cover, you'll want to make sure the maker of your new retractable tonneau cover offers a good warranty. If something goes wrong with your canister, the cover could bind and/or become damaged. The covers that are most likely to have this issue come with very limited / short warranties.