Start with the owner's manuals. If you haven't purchased yet, you can download most online by searching something like "2015 Toyota Venza Owner's Manual." You may find that the rating depends on drivetrain, trim, and/or optional equipment, such as a tow package. A dealer
VIN check can verify whether a particular vehicle has required towing upgrades.
I'm confident a Ridgeline would be fine. AWD versions are rated 5000 pounds. I'm not sure about the Venza. I would want something rated at least 3500 pounds to pull a 2800 pound trailer, assuming that's the fully loaded
weight, not the dry
weight.
Best wishes!