Just wondering what would happen if we went off our sitter's schedule on the weekends - would it make the Monday transition more difficult for our DCP and our son? Sometimes it just doesn't fit with our schedule to go with hers during the weekends, but a schedule is something our son has always thrived on, so we've worked our schedules around the one he's used to.

Depends on your child. If he is very schedule reliant to get through his day, then staying on schedule is a good idea to make his week run smoothly. However, that being said, an occaisional change in schedule is probably good. I mean life doesn't always happen the way we want it to.
DH calls me the schedule Nazi (is that bad)?? I think that if your child thrives on a shedule, go with it. But if you are off sometimes, dont worrry, kids bounce back into routine fast!
Totally depends on the child, but most can pretty easily grasp the idea that when they're at Daycare, this is the schedule....and there generally is much more of a schedule than at home - less done on impulse. The main thing I like parents to keep up at home is if we have a potty training program going or something of the sort, just because otherwise it's basically starting fresh every monday. As far as napping and stuff goes, not a real big deal but it's nice if the child is used to going down at approximately the same time, or for close to the same amount of time, just because that keeps THEIR routine in sync, and they're not overly tired at home or daycare if the schedule is kept more or less on par.
I also think that it all depends on the child. most of them will get back in routine without any problem.
Wow...thought I would add my input but the rest of you covred it completely! Use your judgement and see how the child responds - their flexibility and resiliancy is remarkable.