Adrestia

Landwalk is a generic term that appears within an object’s rules text as “[type]walk,” where [type] is usually a land type, but it can also be the card type land plus any combination of land types, card types, and/or supertypes.

Landwalk is an evasion ability.

A creature with landwalk can’t be blocked as long as the defending player controls at least one land with the specified land type (as in “islandwalk”), with the specified type or supertype (as in “artifact landwalk”), without the specified type or supertype (as in “nonbasic landwalk”), or with both the specified type or supertype and the specified subtype (as in “snow swampwalk”). (See rule 509, “Declare Blockers Step.”)

Landwalk abilities don’t “cancel” one another.

Multiple instances of the same kind of landwalk on the same creature are redundant.

Crew is an activated ability of Vehicle cards. “Crew N” means “Tap any number of other untapped creatures you control with total power N or greater: This permanent becomes an artifact creature until end of turn.”

A creature “crews a Vehicle” when it’s tapped to pay the cost to activate a Vehicle’s crew ability.

If an effect states that a creature “can’t crew Vehicles,” that creature can’t be tapped to pay the crew cost of a Vehicle.

Some Vehicles have abilities that trigger when they become crewed. “Whenever [this Vehicle] becomes crewed” means “Whenever a crew ability of [this Vehicle] resolves.” If that ability has an intervening “if” clause that refers to information about the creatures that crewed it, it means only creatures that were tapped to pay the cost of the crew ability that caused it to trigger.