I'm the type who would find out exactly what my vehicle lacked versus the ones with tow package, and add the components which are needed to protect the drive train. That said, with the non-turbo 3.5L I'd be hesitant to tow anything with a frontal area greater than 7' wide by about 100" high or over 3500 lbs dry. And if I were pushing those limits, I'd keep my speed at 60 mph or less and lock out overdrive.
About the weight... 3500 lbs dry is likely to be 4200-4500 lbs when loaded. Even more critical is the hitch weight, which your vehicle can probably only handle 500 lbs and this is very easy to exceed. I once had a 23' Rockwood of (IIRC) about 3400 lbs dry and 380 dry hitch weight. But the fresh water tank was up front. I bent a rear spring on my 2000 Mountaineer (rated for 6000/600). You'll want to get a scale (Sherline makes a good one) and weigh the hitch before starting out. BTW, for safety you always want at least 10% of the total TT weight on the hitch for proper handling.