I can't speak to the particular van that you originally posted, except that I wouldn't tow a trailer that has the potential to be loaded to 7000 lbs with a 1/2 ton. I just thought I'd add something about dealer pricing, that will hopefully help you in the future. I've been self employed over half my adult life, and employed as many as a dozen people at a time. So I've had the opportunity to purchase many trucks and vans. From what I've gleaned over all these years is that "fleet price" is 18%-20% off the asking price of used, or msrp of new. So I never pay more than that. Now with used there is a caveat, and it may or may not pertain to this one. If they paid too much for the van as a trade in, so they could make the sale of a new vehicle, then even 20% off the ask could be too high, but that is what they will want for it. That's why the best tool you can have in your pocket when you go to buy, is the ability to walk away, no matter how much you like a particular vehicle. If you get up to walk out, and they really want to sell it, they will come down. If not there will always be another deal out there waiting.
Also, never buy from a used car lot near a military base. Those dealers are usually the lowest form of scum in my opinion and take advantage of our young enlisted men and women. I've seen it so many times in various states that it just sickens me and I won't even step on their lots.