With a 5k towing rating I doubt you could pack enough into the car to overload engine & trans--it might still be over GCWR, so I'd check on that, but I suspect it'll be fine.
1,700lb being towed, I'm guessing it doesn't have trailer brakes? I'd be worried about that first, then making sure to get tongue weight correct so as to prevent sway (although keeping speeds low would be good).
Personally I'm starting to worry less these days about oil temps, be it engine or transmission. The OEM's know what used to die in the old bad days and have taken to adding coolers, plus oils are much better today. Be careful when using old school recommendations: they are old today. For example, it used bothered me to read that I should keep my ATF below 150F yet whenever I looked it would be at 190F just going down the road. It took me a while to realize that recommendation's from the 80's did not matter 30 years later. Anyhow, if you can get to the ATF temp sensors (even better, engine oil too?) then that might be interesting to watch while out on your trip. If stuff really does run hot, do short OCI and maybe go thicker on engine oil, if actually required.
It's a pop-up, it's got low wind drag, if you are keeping below 60 or so, and out of the hills, stuff isn't going to run that warm.
