Does this require drilling into my bed or frame?

No. These clamp directly to your factory bed rails at existing mounting points. Installation is completely non-invasive.

Can I open this partially, or does it fold all the way?

Both. Each of the three panels folds independently, so you can open just the front section for partial access or roll the entire cover back for a fully open bed.

What's the maintenance like on a soft tonneau versus a hard cover?

Soft covers are simpler — occasional rinse and air dry. No polishing, no repainting, no weatherstripping replacement. The tradeoff is they're less rigid than hard panels.