Will chains help - it all depends. I use chains a lot on my 4X4s. Usually I take three railer chains for dual wheels on semis, then take all of the cross members from one side and move them to the other side. This removes the third rail so that you can run them on single instead of dualed tires and gives you twice as many cross members for better traction. I have the tool to fix or modify tire chains. I usually run this type of chains when snow plowing in the steep hills and in the mud.
Anyways, you don't have to go to that extreme. Borrow a set of chains and see what happens, you're got nothing to loose anything and the ruts won't be any worse than what you already have. The chains will deffenitly help unless the ground is just too wet. Then you'll just be stuck, but not worse than before. If your trailer axles are dragging bottom, then chains probably won't help.
As mentioned, get a 4X4 to hook onto you, preferably from good solid ground or out on the pavement. Use a three or four inch tow strap and not one of those little two inch straps - you've got too much weight to mess with one of the little ones.
Learned something new - I didn't know they even made two wheel drive Excursions, never seen or heard of one.
Remember this post when some asks about buying a 4X4 vs a 2X4. You don't need them all of the time, but boy are they nice when you do.
Bill
Nodwell RN110 out moose hunting. 4-53 Detroit, Clark 5 spd, 40" wide tracks, 10:00x20 tires, 16,000# capacity, 22,000# weight. You know the mud is getting deep when it's coming in the doors.