Oh yeah, and if you get an efficient diesel generator you're looking at using 14 gallons for that 455 miles of range, giving you 32.5 mpg, which while it isn't great, isn't bad either.
The shipping weight on the first generator you gave was over 400 pounds, so we'll be conservative and call it 350. Fuel is another 7 pounds per gallon, which adds another 100 or so pounds (or more with a bigger tank, although this will go down as the fuel is consumed), and the trailer will likely weigh in the neighborhood of 150 pounds, with the hitch adding another 30 pounds or so. The upshot of this is that with the extra weight the car will be pulling (600+ pounds or so, plus whatever the passengers weigh), you're not likely to get the advertised 265 miles of range, plus if the generator is running at 85-90% of capacity to charge the car it's going to burn fuel at close to twice the advertised rate (which usually assumes a 50% load), both of which will substantially reduce the effective MPG.
It's doable, but not practical. To me it seems kind of silly to spend thousands of dollars in addition to the rather steep cost of the car itself just to turn it into an expensive, jury-rigged hybrid when any $30,000 ICE sedan will give roughly equivalent if not better range, and you have to buy a LOT of fuel to make up that $40,000 price difference (minus whatever tax credits, etc. come into play). And yes, if you happen to have any charging stations along the way you can mitigate the financial cost, but the charge time is far from trivial, even for the Superchargers. For an ICE car that gets 30mpg, it takes about a minute to fill it with enough energy to go 300 miles. For a Tesla on a Supercharger, it takes an hour or so to load not quite 90% of that much energy, and far longer at most other stations.