We enjoy November - typically great weather (warm but not hot and humid, little rain), and the crowds are... well, there's no "quiet" time at Disney World anymore, but November is generally quieter than Spring Break or Christmas, at least. We've arrived on Thanksgiving Day once, and the day after Thanksgiving another time. The crowds thinned out over that weekend and were quite reasonable by the following Sunday. I haven't done the week leading up to Thanksgiving, though. In 2017, Thanksgiving falls on 11/23, so that will put you there for the busiest week of November. You can expect the crowds to intensify over the course of that week, hitting peak that Friday/Saturday right after Thanksgiving, I'd imagine.
What matters most, I think, is going with the expectation that there's no way you can do/see everything in one trip. (That's why so many people go back again and again!) Decide in advance what each of you most wants to do in each park - whether it's a character meet and greet, a handful of rides, a show, a character meal, etc. If your family is full of early risers, your best bet during a busier week is to get to the parks EARLY. Know your top-priority rides, and aim to get them done first thing after park entry. Schedule your FP+s later in the day - after noon, or even in the early evening - don't waste them in the AM hours when the lines will be comparatively shorter. If you want to follow a precise touring plan, there are places that will help you maximize every minute in the parks. I don't do that - there's so much that is scheduled in advance on a Disney vacation, I like to leave some room for flexibility and time to stop and smell the roses. But some people swear by precise touring plans.
Go with the understanding that there will be some crowds. There will be lines. You will have to wait. (Easier for your 8 year old to understand than your 2 year old, I know.) There will also be a lot of walking, which can be especially tiring for the kids. 5 miles is easy in a single Disney day - 8-10 miles is likely if you're in a park for a bunch of hours. Plan your meals strategically - they'll give you a chance to take a load off your feet for a while, and if you like the idea of sit-down meals, those ADRs are vital. Try not to waste morning time at a sit-down meal, though. If you want a big breakfast, eat before park opening (get a pre-opening ADR at the park, if that's your thing). In particular, reserve your Thanksgiving meal FIRST - dinner that night will be a hot commodity when it comes to your 180 day dining mark.
If your family likes to swim, maybe plan some downtime at your resort pool - it's a great break from the crowds to just float and splash and chill poolside. We did an evening swim after dinner just about every night of our last November trip. It was cool after dark, but the pools are heated, and we just hustled back to the room quickly once we got out of the water. It was very relaxing!
As for transportation, are you staying on Disney property? Using Disney buses and such? We always rent a car - I prefer not to be packed in with dozens of cranky people (while I'm possibly cranky myself!) at the end of a long, busy day. But again, there are people who swear by Disney transportation and wouldn't take a rental car if they were given one for free. To each his/her own!
There's so much info out there, and people on these boards are great at sharing what's worked for them - but you have to take it and apply it to your family. (For example, if you know there's no way you're getting your family to the park in time for rope drop, that's fine - just adjust your expectations and know that it will be busier by the time you do arrive.) Have fun dreaming and planning!
