I’m going on a 6-hour trip driving someone else’s SUV. I am the chauffeur for the trip. I normally drive a Mini Cooper, and my other car is a Toyota Camry wagon. I have driven SUV’s just short distances before.
So are there any really important things I need to know? This car is pretty fancy and has the back up beeping thing. I’m pretty sure it’s a Lexus, but I don’t know exactly what it is.
As with driving any unfamiliar vehicle, be extra cautious at first until you get used to the difference in size and handling.
For SUV driving in particular, my tip is to pretend you’re driving a large truck, which means braking earlier and needing greater stopping distances. The SUV will doubtlessly be bigger and heavier than what you’re used to, and if you accelerate/brake/follow like you’re driving a mini, you’re bound to rear-end someone soon enough.
If indeed it is a lexus you can essentially drive it like you would a car. They are made very well, and their SUV’s are rates quite high in controlability. Manuevering (sp?) may be slightly different than your Mini 
however, the drive won’t be like that of an Escalade or Tahoe.
Keep it easy around corners at speed.
Get used to your blind spots because they will be longer than that with a sedan.
Braking should be the same, or nominal compared to the sedan.
Gas mileage may increase.
I drive an Avalanche, and my wife drives a Mercedes-Benz, I have a good view of how each handles. 
In town - USE YOUR MIRRORS!. Otherwise, when you’re seated that high above the ground, you could make a turn without realising there’s someone on a bike beside you. Or even just a kid a bit too close to the traffic. I’ve been on the receiving end of that mistake.
Adjust EVERYTHING to fit you before you take off. Mirrors, seats, etc.
Take into consideration that the pickup is going to be much stronger than in your little car. I have a Honda Civic, and when I drive a Pathfinder, I go herky-jerky down the street for the first twenty minutes or so.
Stopping takes longer. Way longer. Especially in bad weather!! Test it before you get on the highway, a number of times.
Keep in mind your higher and wider than your used to, as the other person said, you can not see, and yet really clock that bicyclist with your side mirrors.
And yes, go easy around the corners, SUV’s are top heavy.
And Stop Tailgating me!! I’m the one in the small green honda-skate in front of you! :eek:
Pretend you’re driving a Truck. 'Cause reguardless of how it ‘feels’, it IS and has the MASS of a truck.
SUV’s are a great, empowering, experience. You have a commanding view and a feeling of control and safety.
That’s an illusion, don’t get sucked in. You’ll be driving something that’s 60% larger and 60% heavier than your Cooper.
We have two Vettes, a PT cruiser (nearly Cooper sized) and an Avalanche. Each provide a distinct driving experience and must be driven appropriately.
Other than that, enjoy the ride! I love the opportunity to experience another vehicle I don’t have to pay for.
If you keep the speed reasonable IT WILL NOT FLIP.
I have done parking brake 180’s in my Explorer. Off ramps that say 35mph are handled way easy at 65. If one looses control of a typical SUV because “it is top heavy” they were way out of shape for the conditions!
As mentioned, adjust everything before you start moving. Maybe just spend five minutes just getting familiar with the stuff you will use such as light switches, window and door locks, alarm system, windshield wipers, steering wheel and seat adjustments, radio…
When people would drive my company truck (bigger than a SUV) they would drive it like they were in their car. I would tell them that while they may feel fine, they should be aware that they are using about 85% of the handling capacity of the truck whereas they might only be using only about 50% of their car’s ability. I would tell them that if they needed more breaking they will be surprised to find that they are almost at max. Your car will brake more with just some more pressure but the big truck is about to lock up.
Have fun on your trip
Forget driving it like a truck, drive it like a sled.
Horses in the front you have to ‘watch’ your speed with - handling carefully until you get to know the engine -
Drive it as though you have something unsecure in the back you don’t want tipping or moving.
I learned to drive vans w/camcorders in the back (oh you drive slow) and when I was learning to drive the pickup we had noisy loose things in the bed of the truck - if it rattled, you turned/stopped/started too fast.
First thing to do when you get in is mess up ALL the mirrors, forcing you to re-adjust them to what you can see.