There is absolutely NO reason you should be making "progress" at...what...37-38 weeks? That's not even normal! And it's not like it would mean anything even if you *were* slightly effaced now, etc. Please don't put that kind of pressure on yourself! You have lots of time. And if you don't want to, you don't have to have a c-section at 41 weeks. The words "no, thanks" are perfectly appropriate if you don't feel like it would be best for you or baby. Feel free just to call after hours and cancel or reschedule for another day (leave a voicemail!). If you don't want to be more direct, you can always invent a cold...surely DS or DD can conveniently get a "terrible cold!" the day before the scheduled surgery! I mean, they wouldn't want you going into surgery already sick, right? Or expose the new baby to a case of the sniffles? Suddenly, that "oh my goodness you HAVE to have the baby out by 41 weeks exactly" becomes a lot more flexible and just not the hard and fast rule they're been telling you it is.
And please forgive me for being a Debbie Downer, but to me it doesn't sound like your doctor is at all supportive, or that he's just trying to "let you down easy". Frankly, he's inventing a reason for you to expect that it won't work out, and he's set a limit on when you'll be "allowed" to deliver vaginally--without talking to you about why he's suggesting a c-section at 41 weeks and asking you what YOU decide.
Because it does, in fact, boil down to what you want. If you are not convinced by his answers to your questions, by his reasons, by what he tells you you "have" to do--just smile at him and say, "well, I'm going to need some time to talk this over with my husband. I'll let you know what I've (or what we've) decided. Thank you!" Repeat, repeat...and leave. Make your decision when you're not right there getting "leaned" on. Check with others, think it through...decide what you think is best, given the circumstances. Hopefully, if your doc IS supportive, he'll want to talk to you and give you the best info he has, and then leave room for you to decide.
Keep us posted, hmmm?
Don't know if you've been memorizing stats on VBACS for years or whether it's all new to you, but just in case, check out http://vbacfacts.com/2008/06/03/hospital-vbac-turned-cs-due-to-constant-scare-tactics/
and the rest of her website.
Good luck, hon. I'm sorry you're feeling under so much pressure. You've done a great job of growing this baby so far, and I don't think your body is going to suddenly bail on you now!