WHile I think there are some great considerations here...I can sort of give the other side....A family member of mine went to WDW - more or less to specifically help her recover from major surgery. WDW was her physical therapy - so to speak.
Honestly, she was very disappointed with the professional physical therapy she got. She was motivated, others in her group therapy were not. She went twice as it happens. once was before teh trip, and once after...they happen to be at the same facility where she works out...She was disgusted with her fellow members who didn't want topush themselves in any way...I'm shortening things here...but weeks later they were still whining and their condition was not improved, while she was totally back on her feet. At WDW, she had
scooter, but tried to walk a little bit more each day.
Her surgery was not minor. While two different people can have two different recoveries- I say if going to WDW is a motivation for her, then it may well be a great idea. And I dont think all doctors 'get' that. Some doctors can be quite arrogant and limited intheri perspectives. I'm not saying you shoudl ignore them, but you should always take what they say with a grain of skepticism. They are humans, not gods. I mena certianly if they say you need CPR then yeah - you shoudl listen...
You may well want to consider
renting a scooter for her. You probably will also have to taylor your trip a little. I will also second, that if any situation warrents the full services of the deluxe resorts - this is it, if affording a deluxe resort is at all in your budget. It could well be worht going to WD fora shorter time and staying ina nicer place.
Heck, I'd even suggest that concierge level is a great idea. There you will have extra staff to help you with anything you might need: last minute reservation changes, calling a taxi, getting extra pillows, getting the phone number for a pharmacy....
Here's the thing...when my sister went - it was last minute thing - she booked a room at ASMo, while we were staying at CR. Many of our dining reservations were at places onthe monrail loop. A scooter at a value resort means taking it on the BUS every time you want to leave - and to dine at ANY TS places - you will need to leave your resort. She ended up leaving the scooter with us, esp when we went to MK. She would meet us at the park entrance so that she didnt have todeal withtaking the scooter onthe bus. One adult stayed with her each night - but all would have been easier if she could have simply stayed at CR with us. (I actually offered to stay there for her, but that would have meant moving all her stuff, and our park tickets were on our room keys - so that would have been a problem.)
If you stay deluxe - you can dine TS several times at your HOME resort. If you stay at an Epcot deluxe: BC, YC, Bwk - you can boat or 'walk' to Epcot or HS - she can sit inthe scooter on the boat. EVen if she only wants the scooter part of teh time. At the every least, getting to/from both those parks is easy. If you stay at a monorial resort witha scooter, ten she can use teh scooter onthe monorail to get to MK, Poly, GF, and CR. It will also be monorail to Epcot - again - monorail is much easier with botha stroller and a scooter. Even if you don't use the scooter - getting around onthe monorail/boat is easier with a stroller because you don't have to fold it up and pick it up - the child can sit in the stroller on both. Busing witha stroller and toddler - to me - is much easier with at least two able bodied adults (i.e able to lift stroller, child, stuff.) WL are kind of 'deluxe light' resorts - but they are compact resorts so that would be aplus. WL offers a boat to MK. AKL is all bus - but if you are confined to the rsort iteslf the food court is decent and the resort has lots of fun activities all day long. The new AKL DVC has an amazing pool play area.
One more suggestion - might be to find a family member to join you. You don't say if you've already made all yoru dining reservations or not...but if you can have an extra set of hand to help - that's abig plus. Our family often goes in extended family groups and even with able bodied folks - one extra adult can be a big help. Too many makes getting around more challenging. Even a responsible older child could be a big help. Cousins?
OH INSISTING on a first floor room will also be a big help at Pop, IMO.
Pop is relatively good for busing, but the deluxes will offer another plus - It is much easier to get back for a break or nap at the deluxes. If you shoudl consider concierge - you will also have food just outside your room most of teh day. Some hours it is only snack foods, but if you do find yourself spending extra time in the room - or even your wife does - getting at least drinks is EASY. At any deluxe - room service is an option. pricey, but an option. I dont thinkPop offers any room service at all. The mods will only deliver pizza to the room.
Further, who says a trip to WDW has to be able being in the parks all day. The two year old will probably love the resort - even Pop. Just about every part of WDW has theming.
I'm not sure a car is needed. I don't see packing up a stroller and scooter to go everywhere as an 'easy' option. Plus, if you have a two year old and rent a car, you'll have to deal with a carseat. The rental car will have to have one with daily fee- or else you'll have to lug one form home. It just sounds more complicated than taking WDW transport to me. If you don't end up getting scooter, then acar might be one way to go...but I'd personally think putting the same money into a better resort would be money better spent.
Of the value resorts, Pop has the best transport. The mods are mostly very BIG, sprawling resorts. Of them only POFQ is compact. The rest have LAKES inthe middle -so they aren't great. If it's available - you MIGHT consider upgrading to preferred location room at Pop. Again though, the deluxes offer a significant upgrade in service and resort amenities.