A pan of hot/boiling water will check the temp gauge- - - -just put the sensing bulb in the water and use a hot plate or a camp stove to heat it up. The oil pressure gauge can be tested with an air hose and a pressure regulator- - - -PSI is the same no matter where it comes from. A battery and a headlight bulb or two will check the ammeter for +/- deflection, with at least a little bit of accuracy if you check the resistance of the bulb filament with an ohmmeter and do a little math. The only gauge that might be a little tricky to test will be the gas gauge.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!