Mounting the gennys on the roof is a bad idea. First of all, they are dense enough to possibly damage the roof. Second, this will raise the center of gravity of your truck and substantially increase the risk of rollover.
I also shuddered at the sight of the large generator completely covering the most important part of the grill. That's the last thing you need when towing.
There are good reasons to have the genny at the front of the truck, though. It is secure, and away from the trailer with its (minimal) noise and fumes. A 2000, or even a pair oriented correctly, might be a better fit than that refrigerator-door-looking 3000 right in front of the radiator.
I know this idea won't work on every TV, but my 1990 Suburban has cubic YARDS of space under the hood and under the rear. The gas tank would have to be dealt with, but think how secure a generator would be there!
Only downside is the fuel economy of this big old thing, like 10 gallons per mile.
The front of the TV is a great place, as long as the radiator gets its air.
For security around camp, I have several thick, non-cheap cables and good locks, and some chain for good measure. The nice thing about cable is, it bends and ruins all but the best bolt cutters! It has kept the quads and bikes safe so far. If I had a generator with plastic handles, I would figure out a way to have a lock hoop of some kind attached to the frame, or bolted deep inside under the covers. Most eyebolts are easy to bend, open, or snap the threads. Consider using a good alloy of bar stock, and case harden it after shaping. A top notch welder can do this easily.
It seems I love the mountains and deserts more than my friends do. I sure miss them!
1971 Streamline Imperial project "Silver Snausage", 1985 Coleman tent trailer, 1964 Little Dipper, 1975 Northwest "Proto Toyhauler", 2004 Harbor Freight folding, still seeking my Airstream.