I had a 2000 Santa Fe, which a pulled with a Sienna, BTW. We also had 2 kids. We finally traded it in for a bigger unit as the kids grew (and we had a better vehicle to pull it.) When the kids started college we looked to downsize. A king sized bed where you can sleep sideways so no one has to climb over anyone was non negotiable. We would have loved another Santa Fe, but they are no longer being made. Somerset (which bought out the plans and hired most of the Coleman staff) was not really producing. I hated the Jayco and Starcraft dealers nearby. We ended up with a 2417 Trailmanor. Very happy, and the bed is designed that way.
How tall are you? The coleman actually is set up for the sideways sleeping, but I am 5'4" and my husband is 5'9", so it worked for us to sleep the other way. If my husband had been much taller, it would not have been comfortable for him. Other than that, I think the Santa Fe is excellent for 2 people.
I think they got heavier as years went on, your Sienna will work, but you might have trouble on hills.