There's not a lot of weight difference between a 2720 and a 3023. We have several owners who tow with a Sienna. Most of the mid sized Toyotas we've looked at closely allow a full 3500# of trailer on top of the tow vehicle payload. In other words, if your Sienna was rated the way other manufacturers do it, the tow vehicle payload plus 3500# is probably going to be in the 4300# to 4700# range.
More to the point, there are a number of happy Sienna owners in this forum towing TrailManors, and owner experience is worth a lot. To make it work, you'll need to travel light, manage your load carefully, drive conservatively, and always use a Weight Distributing Hitch, of course. But then, these things aren't bad ideas for most of us anyway.
However, there are also some of our members who started with a Sienna and then decided they needed more TV, and there are a lot (most?) of our members out West who describe a need for bigger tow vehicles to be able to get to their favorite places. If you search on "Sienna" in this forum, you'll find a lot of discussion and first hand experience. I'd suggest reading your owners' manual about towing and see what you think, and contact some of our past and present Sienna drivers by private massage to hear their recommendations. I tow with a Highlander, and here are my numbers on the truck scale:
http://www.trailmanorowners.com/foru...ad.php?t=10652
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