Advice for poor would-be adventurers

The primary weapon of the Legionary was the shield.

I don't think a quarterstaff would be very effective against a full plate, those things are well padded. Maybe if you get a good swing with a metal-shod one but getting a good opening to do so without getting stabbed or wrestled yourself wouldn't be plenty.

That is wrong.

It's frustrating how people underestimate the shield, it probably got used more often through history than the likes of a club and spear. Hell, maybe not in a battlefield but you still see shields being deployed by some forces.

The shield's primary use was to protect the individual from missile attacks.
Spears are the universal weapon until the common use of firearms.
Even then bayonets were still utilized like spears.

They had javelins as a throwaway weapon. Their main weapon was the gladius and shield.

...

there are surviving accounts of swords being sold at auction for as cheap as a pence, but if even that is too much a quarterstaff is still effective and you can make yourself.

probably in a place and time where there was a glut of swords.

Hunger, thirst and heat are you biggest enemy. Overextending yourself to the point you don't have enough ration to make the way back and having bad luck at foraging (assuming you know how to properly forage without getting poisoned) is worse than facing a band or orcs.
The heat can exhaust you before even seeing action, more so if you properly cover yourself to avoid dying to some ridiculous reason like surprise snake bite.