I would recommend five vehicles which are not trucks, have 4WD, have towing capacities of 2400lb and 2700lb, and get gas mileage in the 20s on the highway. Two of these vehicles have H-4 engines of 2.5 liters; which are more powerful than most 4 cylinder motors. I have driven them and found that the performance is comparable to some V-6s. The other three have a 4.0 liter V-6 a 3.5 liter V-6, and a 3.0 liter V-6.
These vehicles are the Subaru Outback wagon, the Subaru Forester SUV, the Toyota FJ Cruiser, the Toyota RAV4, and the Mazda Tribute. The Edmunds comparison for the 2009 models of these vehicles can be accessed from the link below.
My own sense of the significance of these comparisons is that the RAV4 has a towing capacity of just 2,000Lbs; which I consider borderline for towing a 2,000Lb boat. The RAV4 also has significantly less ground clearance than any of the other vehicles. So I am not totally enthusiastic about that particular vehicle for this specific application (although I have a high opinion of the RAV4 for.most other uses).
The two Subarus get the highest fuel economy, and the Subaru Outback also has the lowest price of all 5 vehicles.
The Toyota FJ cruiser has the largest motor and the highest towing capacity of the group. It is also the heaviest and longest vehicle. And that would tend to make it the most stable. But it also is the only vehicle that requires premium unleaded fuel.
The Mazda Tribute is essentially the same vehicle as the Ford Escape; but it is priced lower.
Having spent a great deal of time answering questions on this site; I have seen a substantially greater number of problems with Jeep vehicles than with most others, so I would not recommend a Jeep.
I hope this information is helpful.