You should be 127% prepared for Nov 2020 if you research what you need to now. Congratulations on not being one of the hundreds of ppl you'll be seeing that have no clue what they are doing.
The resorts are priced by what amenities they have AND ALSO their proximity to parks. Time is at a premium at WDW. I factor that time in my resort choices. If I can WALK to a park instead of walking to a bus stop, and then waiting for a bus, and then riding a bus - that is MONEY to me. I like to stay at an EP area resort for a known travel time of only a few minutes to TWO parks. Those parks happen to be ones my family really enjoy, so I can figure out real value for travel time if we plan on being at those parks a few times during our stays. We also buy hoppers for this reason. I can be at DHS or EP in 15 minutes, or back in the room from those parks in 15 minutes. I find real monetary value in that over the course of several days.
The dining plan allows you to average out your meal prices. That's all it does. If you order a meal over or below the cost of that prepaid average, then you lose or gain money. You will not get refunded any money you prepay for, but do not use. If you use that money on items you'd never buy in a zillion years, I'd consider that wasted money. If you choose a dining plan, it's pretty simple to figure out if the money will work. Most ppl can make the money work pretty well by doing character meals with kids. The math is easy though. A lot of ppl will tell you that the meals can be pretty big, and the regular Dining Plan will be a LOT of food unless you plan it out well. The dining plan would take a lot of work to make the math work for my family, and even then, it would be way too much food for us, so we could break even, but we'd be tamping food down our gullets. We pay for our meals out of pocket, and we eat like absolute pigs anyway, and still save a whole bunch of money over the Dining Plans. "Free Dining" will lock you into paying for other things at the resort or ticket option you may not want or need. Free Dining is not free for everyone. There is still (simple) math to be done to determine if free dining is worth it for you.
Tickets don't have too much fluctuation in price vs the overall cost of your vacation. You're gonna spend too much money. Get over it. Plan the living sh*t out of this vacation and enjoy watching the girls make memories of a lifetime.
I will also say this:
Don't immediately scoff at paid events like dessert parties, or the exclusive park time pre-paid events. Research them to see if they are right for you and your fam.
Don't be on the go all day and night even though you wanna get the most out of your $$. Plan ahead SO you can relax while you're there. Don't run the fam ragged.
Start a family walking regimen several months before your trip. Go ahead and research how much most people walk per day in Wallytown.
Have a budget, suuuuuure. Have one. Whatever.
If you happen to be a Costco member, check out their travel section for WDW pkgs.