Hey, for at its worth I tow my Evergreen ascend 232bh (a layout I think you'd like!) with a 2015 Grand Cherokee V6. The trailer weighs about 4600lbs before putting in food, clothes and water and the V6 tows it wonderfully. Now, I've only had it out a few times and never into the mountains or anything like that, but I don't think you'd have any issue at all towing, especially with a V8. It's a great car to drive in, very comfortable..you won't be disappointed!
From what I've seen on these forums there are just some people who seem to think you need some massive truck to tow anything and that there are just no other options. While I suppose more power isn't a bad thing, a good SUV like the Grand Cherokee would pull your trailer without any problem and anyone who tells you it wouldn't probably hasn't ever tried it!