Your Lynx only had a 1.6 gasser with tall gearing. When we had four people in the car it was hard to hold fourth on most hills. My old 2.2 Perkins was good for towing 3500 lbs (although slow) and my little 1.9 TDI is comfortable with 2000 lbs.
If you're serious about down sizing or having a smaller vehicle pull your sleds, the small gasoline V6's of today, EcoDiesel or mini Duromax would be good choices.