I own a 2011 JKU Sahara. It doesn't sound like this is a terrible deal for you...
With that mileage, if it is indeed bone stock, I'd expect that you'll be replacing front end joints pretty quickly. As stated above, stock ball joints are junk and will cause "death wobble". Also expect tie rod ends, steering stabilizer, and front axle u-joints in the future at some point.
My 3.8l does burn off about a half quart between oil changes. I read somewhere that Chrysler finds a loss of one quart per 3000 miles to be acceptable. Not that that will make me feel warm and fuzzy at night but at least they acknowledge that this motor loses oil. Not a big deal, just stay on top of general maintenance. The 3.8l is 202 hp (or around there, I'm going by memory) and the 3.6l is 285 hp (again, I may be a bit off, from memory) so naturally the 3.6l is a nice upgrade but my 3.8l does okay... I have a leveling kit, JKURHR springs and shocks, and meaty 33's. It doesn't love turning these tires but it does so under protest. I wheel my Jeep, not super hard, but hard enough. I also have a LOT of added weight (steel bumpers front and rear, skids and sliders, winch...). It's not made for high speed highway driving. It's a box on wheels. As long as you know that going in you'll be fine. It sounds like she probably won't get too crazy with it anyway, if for no other reason than aftermarket parts are $$$$$.
All in all, I LOVE my 2011 and the only reason I'd consider trading it would be to get into a 3.6l but it's not enough of a bother to me to actually make a move. If she loves the Jeep and the money is right I'd say grab it. It won't be anything like the YJ. They've come a long way since then.
Edit: Also, a hitch doesn't necessarily mean it has a tow package. Hitches can be had from Quadratec for about $70 and it takes 10 mins to bolt it on. The 3.21's, if correct, will be the worst part of that Jeep. I've got 3.73's on mine and it's not bad. Wish I had 4.10's but not enough to re-gear (+/- $1000). Also, just to clarify the transfer case, Rubicon's have a 4:1 where all others are 2.72:1. If you're not going to wheel it HARD then there's no difference to you. At Rausch Creek Off Road Park I wished I had the 4:1 for some of the areas in the playground.