Actually, the standard rooms at the Grand Californa are a bit smaller than the rooms at the
Disneyland Hotel or Paradise Pier. The GC rooms are 353 sq. feet, while the Disneyland Hotel rooms range from 364-415 sq. feet--with the average being the the 414 feet rooms.
Also, we are often given a daybed room simply because we are a party of 5. The GC assigns rooms a few days prior to arrival, and they do their best to give parties of 5 these rooms in order to avoid the whole sleeping bag on the floor scenario, despite check in time. We have never checked into the GC before noon.
At least this has always been how it has worked out for us! It sounds like you had a nice visit to the hotel, despite getting locked out on your last morning.