Disagree with a much of what JZcubed posted, except CR as a top option and cruises are a waste.
If you, I'd opt to stay in a suite at CR (or GF main building if you prefer.) If a suite seems too crazy $$, then try a Standard view Club level room at CR. (Actually a very nice view of the lake) The CR lounges are a great place to watch the fireworks. Less scary for your toddler, easy to room post-fireworks. If you think the toddler will be in bed by then maybe go MK view. Club level also = continental breakfast, and snacks/drinks all day. It won't replace full lunch/dinner, but includes added level of service. CL lounges are also a nice place to meet up after naps. If you stay CL, I'd maybe skip Cali Grill. (It is a very SLOW meal for a toddler.) It IS an easy option for your day, but you might prefer dinner at Poly/GF for variety. (WL is also an easy boat ride away.)
To me, Bay Lake Tower is a big downgrade over the Main building of CR (Tower), esp w/ a
scooter, esp compared to Club level. CR tower =covered access to all monorail ADR's except Narcoosee's. Easy access+ variety. Getting to BOG (or World showcase) in pouring rain with a scooter is NOT an option (been there!). BOG is in the BACK end of MK. I love the WS for dinner, but it is a bit far from CR. If you pick Epcot area resort, eat more over there, but favor your home resort.
I disagree strongly about Epcot being boring for kids. My extended family has always adored Epcot. The Kidcot stations are a great free activity! I'd just tell your little one - before the sit- that they will color the image later. Maybe let them do one small part at each station, or let them color at the dinner table. (most TS places give them free crayons anyhow). Also beware the Kidcot markers stain! Still, it is fun and educational to get a stamp in each country! We also LOVE the Living Seas and the Land's boat ride.
WDW offers toddlers lots of little places to play while adults ride the bigger rides. If your child naps in their stroller that's also a good opportunity for a thrill ride. Toddlers enjoy exploring the post-ride area of Test Track.
Instead of the Castle, I'd pick 1900 Park Fare. Better food, better characters, easy with a scooter, especially if it rains. It is also another GREAT lobby! Again, if money is no object, staying in the main building of GF= daily live piano players and big band music. If you just go for dinner, hanging out pre- or post-ADR is relaxing and fun, esp if you DD wears a (princess) dress and likes to dance. GF also offers all kinds of luxury services!
I agree fireworks cruises are a waste, esp w/ free shuttle boats. We also once rented a (afternoon) boat. It was kind of neat, but even that was a bit $$ for what it was.
Also, all the deluxe resorts have free resort activities.
You can't bring (most) scooters easily in a car. But if some walking mobility is an option, and you'll have your own car, we always enjoy an evening at AKL paired with dinner at Boma. After dinner, it is a short walk to see the Animals and lobby art. Staff is on hand with night vision goggles, and tons of information about the animals. There's also 2 fire pits (one inside, one outdoors), and plenty of places to sit. It is also easily accessable via taxi, but getting to AKL via bus is a royal pain- Especially with a scooter.
If money is truly no object- I'd say the one big downside of WDW with a scooter is using the Disney buses. Doable, but you may want to limit how many times you do it. Some folks don't mind, others hate it.
One option might be splitting your stay between an Epcot CL deluxe and CR, if everyone is game. Then your only bus would be to AK. another option would be to get a scooter which can be folded into a trunk. Option 3 would be having your own handicapped van. I think you can rent them. (I DO know one company rents medical equipment beyond scooter to WDW guests.) Shop around for a scooter rental.
Still one more option- esp with a CR stay, is to spend an evening seeing the Hoop-Dee-Doo dinner show. The show is an absolute hoot for all ages, and is a simple shuttle boat away from CR.
Beyond those, even if money were no object, I'm not sure what else appeals to us. Maybe a ride in the glass carriage, that would be fun. You might also want to book one of the special private photo sessions. We've never done it at WDW, but we did one elsewhere. A nice portrait of the entire family will be treasured long after the vacation ends.
