This is a tough one.
The 4Runner holds its value because they are so much more reliable than any other similar vehicle.
Will you often be towing 5,000 lbs., or usually only the same load you've been towing with the Sienna? For frequently towing a heavy load, I do prefer an SUV to a car-based crossover. I also don't think they started rating crossovers for 5,000 lbs. until fairly recently, so used ones with this spec will be well over $10k. But for infrequent towing of the sort you've been doing with the Sienna a crossover could be okay, especially if fitted with sufficient engine and transmission coolers.
The domestics, Nissan, and Kia haven't fielded a reliable midsize true SUV, so there aren't any I feel comfortable recommending unless you're willing to take a chance on a few repairs. Then maybe a Ford Explorer (iffy transmission with the 2006) or Nissan Xterra or Pathfinder (make sure the radiator has been updated on the 2005-2007 to avoid a failure that kills the transmission, most but not all have).
The full-size SUVs (Tahoe, Expedition) seem more reliable, but then you're dealing with a very large vehicle, which wouldn't be best for a new driver.
Also worth keeping in mind is that the older the vehicle, the less likely it would fare well in the latest crash tests or to be equipped with stability control.
Sorry I don't have a good answer. Cheap + safe + reliable + AWD + 5,000-lbs towing can't all be done in the same vehicle.