I replaced my rear wheel hub assemblies on my '05 a few weeks ago, and there are certainly a few differences between my van and yours, so take that into account, but:
1) The 4 bolts that hold the assembly in require a fair amount of force to remove. I hit them with PB Blaster a number of times for a few days before I started. I also found it helped to get an 18mm universal socket to fit in there.
2) The special tool works to get the hub assembly off and does not damage the bearings, but the special tool is rather expensive. If you're not going to re-use the bearings b/c you're replacing them, get a slide hammer and a wheel/hub adapter from an auto-parts store and it will work.
3) Separating the old hub assembly (which I was replacing) from the backing plate (which I was re-using) required a lot of strategic heat, penetrating oil, and pounding with a hand sledge and cold chisel while the entire backing plate/hub was suspended in an ad-hoc wooden frame. The first one took me the better part of 45 minutes to separate. After learning my lessons, I got the next one a lot faster.
All that said, make sure the bearings really are the problem. I just replace mine b/c they were the problem, but my van also had 137,000 miles on it at the time.
'05 Town & Country Touring
3.8L 180,000 mi