You could bring a battery, jumper cables, short jumper wire and a compression gauge
Remove all spark plugs first
Unhook starter motor wires, should be two of them
Hook jumper cables up to starter and engine ground
Put short jumper on the positive jumper cable, at the starter motor, you will touch the other end of this wire to the "S" connector on the starter to activate starter, so make sure it can't short to Ground
Make sure radiator is full of coolant or water
Crank engine over a few times with no spark plugs, it should rotate very fast
Listen for any knocking or tapping sounds
Watch spark plug holes for any vapor coming out, i.e. blown head gasket/cracked head
Then test each cylinder for compression
3.0l runs 9.3:1 ratio so expect about 160-165psi at sea level, a little lower if above 2,000ft elevation