The '03 Excursions with 7.3L diesel engines are overpriced for a reason. The last hurrah for the 7.3L diesel was reliable as a rock. The '03 GM diesel was still too new to be proven reliable. But GM and Issuzu did a good job on that engine, and GM owners swear by them now.
So now you have probably enough tow vehicle to haul your family and tow that trailer without being overloaded. But provided only that you watch your weights. As I mentioned in your other thread, full-size SUVs can either tow a heavy trailer or haul a big family, but usually not both at the same time without being overloaded. So weigh your rig often when on the road, and know where you stand.
And pay attention to the aim of your headlights when towing. If they are pointing at the stars and blinding oncoming drivers, then you need to install RideRite air bags in the rear suspension.
Grumpy ole man with over 50 years towing experience. Now my heaviest trailer is a 7,000-pound enclosed cargo trailer, RV is a 5,600 pound Skyline Nomad Joey 196S, and my tow vehicle is a 2012 F-150 EcoBoost SuperCrew.