Land Vehicles

1. Pedal Bike
2. Motorbike: quick and easy to nip around no Cargo space easy to fall off
3. Electric moped: same as above but needs to charge in charging station instead of fuel
4. Electric car: same as electric moped
5. Armoured car/ tank: A car with plate armour and a bigger gun ...

i think low level tech you could walk around and hold a metal detector which pings when above metal and a spade to excavate the dirt to reveal the goodness beneath
later you could modify a car to carry to carry the detector and a data logger computer to mark the places on the map
a JCB digger type ...