Starwood Preferred Guest - Westin Mission Hill room size?

I booked the offer for 4 nights at the Westin Mission Hill for next March. ($289 for 4 nights and 10,000 SPG points was too good a deal to pass up). Anyway, we will probably be bringing 2 kids (6 and 8) with us. We are booked in the hotel, and not in the timeshare. How large are the regular hotel rooms? I've seen pictures where the room contains a full size sofa and seating area--is this true of all the rooms, or only of some rooms? I'm asking because if the regular rooms are on the small side, it might be nicer to book a second room as well. Also, I don't have any status with SPG (besides preferred plus from the AMEX card) so upgrades will be extremely unlikely.

The regular rooms are pretty well sized. You will have enough room for a roll-a-way. The room pictured on the website is a standard King room. A double room would have another queen bed in place of the Sofa/Table.