However that would also mean that the car can be recharged from 0% to 100% in 40 minutes - and that is not what happens in reality. Initial charging is faster, and as you say the last 5% may be not even desirable.
Like I said earlier, for longevity purposes Tesla actually has their system report it's full and stop charging at about 80% of the maximum charge it's battery pack could actually take. That avoids the 'last 5%' slow charge problem pretty much completely, as a LiIon battery pack will still be charging at a good rate until it's over 90%. Figures are approximate due to variability in chemistry, battery size, what's considered a 'fast charge', etc...
Wiki and other sources are quoting 'about an hour' for a full charge, with 50% being 20-30 minutes, but then Tesla's website mentions that they're upgrading(have upgraded?) their supercharger stations to make charging even faster, so the 30 minute references might be for the older stations. All figures are for the longer range 85kwh battery.
However EVs cannot pull a trailer.
They can't? I mean, google has all sorts of hits...
Once the manufacturer installs the hitch, they cannot control what kind of a boat, or a horse carrier, or a heavy trailer will be connected there. They'd need to come up with some nonstandard interface, that is guaranteed to only support the charging trailer.
Actually, they can. My light truck, for example, has a class II receiver(3.5k pounds), which is 2". On the open market I can only get class 1(2k pounds) or 2 ball mounts that fit my receiver. If I had had the tow package, I could have put a class III on(5k pounds). With a regular EV, you'd get one with a 1 1/4" opening, which you can only fit the smaller ball on, thus only the smaller trailers with that type of hitch.
If somebody goes through the effort to custom make a 1 1/4" bar with the larger ball in order to hook up a large boat to their EV, the damage is going to be warranty voiding obvious. Most of those things are designed to hook into a special hitch installed into the bed of a pickup or on an actual semi.
Meanwhile, there's all sorts of instructions in my truck on how much I can tow. There's stickers on trailers as well, all I have to do is play 'equal to or less than'. Places like U-Haul are well used to educating users, and have a selection of light tow trailers that even smaller cars can haul. I figure they'd be the ones renting out the generator trailers anyways.
There is yet another issue. Most people do not know how to drive with a trailer - not just in reverse, but even forward. I guess they could learn, but the clientele that buys EVs is fairly demanding.
I learned in the course of a day. I wouldn't rate myself as expert, but some of these models are designed to help prevent jackknifing when backing, and you shouldn't be doing much of that given that you're only going to be using it(theoretically) on the highways. I learned with a 3k pound loaded trailer without fancy steering.
I priced that rental online, and it was more than $500 for a week.
The price I found was $320 for a SUV from Enterprise, like I said. Your dates might have been bad, or the area expensive, etc... *shrug*, rental prices vary a lot. As for snow chains, well, I own a set, they aren't cheap, but well, I live in Alaska, paranoia is professional for winter up here.
$20k would get you a pretty good older used SUV as long as you're careful. But transaction, registration, inspection, and insurance costs would eat up any savings from buying if your use is irregular enough. I'll note that you didn't buy an SUV instead of renting, you delayed your trip.
But, I guess, everything is expensive with EVs; if you have to ask for the price you cannot afford it :-)
Same can be said for many things; I'm warped, both parents are accountants. I do those sorts of figuring as a routine matter of course.
If you're not attached to your vehicle, rent one. If you're attached(or going one way) rent a trailer. If you're going camping, figure the ability of the trailer(and car) to provide electricity in remote locations. If you get a light enough trailer you can move it by hand if necessary. Heck, I can do that with MY trailer when it's empty, and it's a covered trailer big enough to put my motorcycle into.