looking to buy a trailer which weighs in right at the max tow limit of my 1999 F-150 V6 with a 3.31, Ok it weighs about 400lbs more.

Everything I've read says keeping the tranny oil cool is key.

The majority of the time I will be towing the trailer no more than 20 miles to a local beach. I have the following questions I need help with:

1. What problems should I expect in towing a trailer at the limit?
2. Should I install an trans oil temp gauge?
3. Should I install a transmission oil cooler? Which one?
4. What else should I look to install?

I guess the last thing, is am I overreacting?

Thanks for your help!