The valve check/adjust and timing belt are good preventive maintenance and should definitely be done if you intend to keep the truck for a long time. A valve out of spec can get burned, which is an expensive fix. I wouldn't expect the noise to change much though.

The steering boot is a small seal where the steering shaft goes through the firewall. When it gets old and falls apart it lets the engine noise in the cab making things seem more noisey than they should be, especially if you've got an exhaust leak, etc. Its a common problem with a cheap/easy fix.