OK, I verified that I can check in early AND do curbside check in at SFO. Also, I have Clear (
http://clearme.com), so I can take the kids through with me and security is WAY less of a hassle. When the old Clear was at SFO they were actually helpful. DH needs to get his own free trial card or he'll be going through the long security line on his own.
So the airport process will hopefully be not so bad. Also the itinerary is looking like we'll have more time in Toronto on our own so the stroller will make that more enjoyable.
Decision made - going to take the bag out of the box and practice tonight.