Re: Trailering 400 miles thru the northeast. Ideas/Suggestions/What to look for?
Md, to NY? Piece of cake... I towed my 7,000 lb rig with an F150 4x4 from Ft. Meyers FL to NY, in Feb a few years ago. Brand new tires 1/2 hour after picking up boat, grease bearings, check all lights and brakes and off we went. Was a perfect tow, until an unpredicted snow storm hit as soon as we crossed into NJ. Was supposed to be just rain. 160 miles of snow storm. Argh....
Your tires may just about be at the end of thier service life, at 4 years old, but maybe not. Just check real close for any dry rot and keep the pressures at the sidwall max rating. As others have said, good tires, a spare, bearings, lights and brakes are what you need to check on trailer, and have sufficient equipment with you to tend to road side problems. (Boat US Trailering insurance a BIG plus, too) Just take your time and be careful / aware of everything and stop often to check everything out (easy to do since gas milage on your tow vehicle will drop like a rock with the boat back there) and you'll be fine. Since the boat isn't too big, should be easy, but your V-6 Explorer is is a little on the smallish side, so just take it nice and easy.
One suggestion: if you have an IR thermal gun, bring it along and check bearing / hub temps with every stop. That'll tell you if you have a bearing heating up. Or just feel each hub for anything excessively warm.