Right, for your door light thing flicking on and off I'd suggest trying the tailgate, perhaps the tailgate needs tightening down a little..
A good offroad trip might shake a few things loose, though if you aren't barrelling down tracks at 40mph you shouldn't have too many problems.
The brakelight is an adjustment of the brakelight switch, if you lay down across the floor in front of the drivers seat and reach up along the brake pedal and follow that with your eyes you'll come to the sensor switch for the brake lights.. you can usually wind it in a little and adjust it, you might need a spanner/shifter or pliers but you can adjust it in a little and tighten it up.
Oil light sounds like a loose wire, I don't know the V6 engine but it'll be just like any other engine in that on the block of the engine there will be a set of sensors, with the engine cold (so you don't burn yourself) go and push ALL the wires around the engine and make sure they are tight..
Also, check the oil level and if you keep having the same problem with the oil sensor get an oil change (do it yourself, it's a lot cheaper and it's piss easy!)
Perhaps I can offer more info if I know more but the above gives you a starting point.
Oh yeah, I'm new here too, so welcome to the forum. At least someone is offering help with your problems, hehe
Good luck,
Simon