• Add capsule trigger colliders to all IVA ladders (and handles?) - both sides where appropriate.
• For future VR support, individual colliders per rung with collision enabled will be needed.
• Attach to or detatch from the ladder via the Use key. In gravity, detach via moving away from the ladder when grounded.
• Disable normal movement system, new movement relative to the ladder collider direction.
• In zero-G, allow climbing the ladder while facing in either direction.
• View system should be restricted relative to the ladder in both gravity and in zero-G (or: how should overhanging/ceiling ladders be handled under gravity?).
• Add sounds for grip, release, and climb.
• On reaching a set maximum force, lose grip of the ladder (check stock for limits if available).
• Allow directional jumping off the ladder like in EVA.
• Support multiple connected ladder systems, including tilts and curves.

I've set up a basic system that's less binary on/off the ladder (also only applies in gravity). I'll keep this issue around as potential refinement though.