Checked the manual and spoke to Chrysler tech.... MTW with 2 adults is 3700, CVWR is 8600. The true empty weight of this particular 18o is 3211 so we can tow with our van. I was wondering if any minivan owners had any issues towing a 108 /181?
If I'm interpreting MTW as "Maximum Tow Weight" you may have a bit of a problem. If the empty weight of the 180 is 3211, then you have (3700 - 3211) = 489 pounds for your water, food, and gear in the trailer. However, the Heartland mpg site says that the 180 has an empty weight of 2574 pounds and a gross weight of 3800 pounds. Water is 8 lbs/gallon, so if your fresh water tank is full you have 288 pounds of water there. Granted, you can travel with far less, and fill the tank at the campground.
Looking at the weights page, the 180 would seem to be the best for you, since it is the lightest of the mpg family. If you can keep your gear down you should be able to get by until it is time to trade cars.