3/4 ton van can be a good choice. Things to look at - some engines are de-rated for use in a van due to high engine heat and subsequent cooling issues. The diesel engines in the Ford vans were almost 100 hp less in power (and far more reliable for it). Axle ratio is always important, vans sometimes are spec'd with tall axles for fuel mileage and suffer towing. Some van's extend the chassis behind the rear axle for the longer versions, some extend the wheelbase. You want the extended wheelbase if you go for a long van. But overall a 3/4 ton van is a really good match for a 8,000 lb trailer, with the right engine and axle. About the only downside in some situations is lack of a 4WD option.
I towed with a GM Express van 2500 for five years. It was a good tow vehicle, did the job fine, it was just a horrible truck. Bought it new for $40K out the door, got $5K in trade after 5 years and 50K miles. The interior trim literally started to fall off on the drive home from the dealer.