Engaging the tow/haul mode always starts the gas engine, but doesn't defeat electric-only operation...call it the powertrain planning ahead. There is every indication it would pull max load just as you'd expect from 385 horsepower and 380 pound-feet, and the gas you save getting there can be poured in the boat tank. With enough speed on and trailer surge brakes tuned to typical operation, going into regen mode--either by tapping the brake pedal or downshifting--will often trigger the surge brakes: Make sure you tune them carefully so they don't take over the retarding, robbing you of battery-pack recharging.
Of all the reasons Chrysler cited for needing a big SUV--and noting it's a "growing market"--we heard none mentioned in the Aspen owner demographic, only that of the Durango. However, even if the Aspen does go away as redundant, it didn't cost anything to include it in the program and expose a second brand to the hybrid hype.
Both run in the mid-$45,000 range--the Aspen apparently has $230 more in chrome, wood grain plastic, and boat-hull hood stamping costs--there are just a few options available: moonroof, DVD entertainment, trailer-tow package with four- and seven-pin connectors at the tongue, and perhaps a few shades of metallic paint. The blue "HYBRID Two-Mode Hemi" badge implies two-mode applies to the Hemi and begs the question, "What color badge would a BlueTEC diesel get?"
Relative to a 4WD Hemi's 8700-pound limit, the hybrid versions give up about 2700 pounds in towing capacity. An apples-to-apples comparison can't be done, because the top Hemi rating applies with an optional 3.92:1 axle ratio (7200 pounds with standard 3.55:1) and the hybrid comes solely with 3.21:1 gears. However, since the upgraded axle is cheap, the Gross Combined is 2300 higher, and the base truck is almost 400 pounds lighter, it's clearly superior for towing anything more than moderate trailers on crowded routes.
Although GM's Tahoe hybrid ratings are similar, Chrysler folks told us this pair is rated at 6000 pounds because all reverse propulsion is electric (the "low" electric motor runs backwards)--the Hemi may be running to charge the battery, consume fuel vapors, or generate heat, but the motor does all the work. Since bad things can happen when an electric motor "stalls" and ancillary systems and controllers might overheat if overworked, grade testing in reverse yielded the 11,700 GCWR and simple math gives the 6000-pound rating.