Sod it I'll take a stab.
I'm ignoring DL and outside of Florida projects. I'd probably sell those off under strict conditions that they are kept and maintained in an appropriate way.
At WDW I'd immediatly increase hiring of imagineering, and start construction on a new Imgineering HQ that would provide enough space for whatever they can dream of.
I'd likely raise ticket prices with a commitment that it would be temporary. To counter this I'd reduce merch and food costs, but increase quality.
- A detailed cleaning and restoration program would begin, and to reduce disruption would be done overnight to avoid closing rides. Every night a team of workers will come in and work on swapping out dodgy animatronics, implementing improved ride effects, repainting, cleaning, etc.
- I'd get Tron bloody finished even if it meant hiring several thousand workers to get the damn thing open, it's taken far too long.
- The Swiss Family Treehouse would be closed and demolished to make way for a new Up based ride, this would see you entering Carl's house and boarding a 'sofa' style chair in his living room. The ride vehicle would start to rise up on a platform before connecting to an initally slow moving track simulating the house fllying away. A 'gust of wind' would send the ride on a faster journey through adventure.
- Tom Sawyer Island would be closed and rethemed - it's tired and dated and provides practically no reason to go there right now.
- All projection equipment at places like Philharmagic to be replaced with the latest and greatest.
- Work would begin on expanding tomorowland, Tron's a terrible IP so that would within 5 years be retheamed. A couple of new rides would be added here and likely the closure of some crappy ones like Laugh Floor.
- Mission Space would be closed and demolished (more on that in a bit)
- The Oddysey restaurant would be refurbished and reopened
- Spaceship Earth would get it's much needed overhaul
- New countreis would be greenlit in the World Showcase
- Harmonious would be ditched, along with its ugly barges and replaced with something more appropriate
- Journey would be given a total revamp, replacing the current itteration of Figment. The upstairs DVC lounge would be convered back to guest space with the rainbow corridor being rebuilt. There would be a strict 12 month policy on everything in here so as to avoid the crummy outdated tech issues it faced.
- Play Pavilion would be reinstated, however the WoL building would first be given a major overhaul to get rid of the nasty moldy look it currently has.
- Test track would be closed and rethemed
- The Mary Poppins plans for the UK pavilion would be reinstated.
- On the land that Mission: Space occupied, a new Space pavilion would be constructed. This would feature 2 new e-ticket rides: Ticket to Mars (a rollercoaster and motion simulator combination, featuring Tom Hanks as your pilot and Sir Patrick Stewart as your CapCom) and Asteroid Impact, a bodywars style simulator ride where you mine an asteroid for valuable resources, but everything goes wrong). The new pavilion would also feature smaller educational attractions, one of which would let you build your own colony on mars and overcome the issues of resources.
- A new live events stage would be themed into the currently being built part of futureworld. This would overlook the lake and act as a larger theater for things like the candlelight processional, as well as live music and entertainment every day.
- All showcase pavilions would recieve a major update, bringing in more culturally relevent content with the goal of educating.
- Improvements to walkways to help in summer heat.
- The park would recieve two new lands: Animationland and Movieland (those names suck a bit so would have to come up with something better). Animationland would add a couple of new rides, and bring back some elements from the backlot tour to show how animation was done, and how it's now done. Movieland would bring back even more from the backlot tour, and would cover a large area with new movie sets (not just the typical new york streets everyone does).
- This is the one park I wouldn't mess with too much.
- I would close and destroy the whole of dinoland. It would be replaced with a new land caled Beastly Kingdom. This would bring back the original concepts for this area. I'd likely throw millions at Joe Rhodes to come out of retirement, and take full ownership over the park with an unlimited budget to do whatever he wants with this section of the park, as well as others.
- Typhoon lagoon would be demolished. The land from the park would be used to create an ultimate water park around 2x the size of Volcano bay.
- Once this new water park was open, BB would be demolished.
- All monorail train would be replaced with walkthrough next gen versions, and work would start on extending the line to Hollywood Studios, Animal Kingdom, Disney Springs and as many resorts as feasibly possible.
- The Magical Express would be immediately be reinstated, however wouldn't be needed for too long as the monorail will be extended to MCO, with the next gen trains being able to achive much higher speeds, and with a larger fleet.
- The Transportation and Ticket Center would be demolished entirely, to be replaced with a new welcome center, acting as a hub providing direct transport to all parks and resorts.
- All car parks would have solar 'roofs' installed above each space, with every space getting a charger which would be free of charge for guests to use. The same would be done at the resorts.
- Trams would be reinstated at all car parks, with new electric trams being ordered to replace them as a short term solution.
- Longer term an overhead people mover system would be added to all car parks.
- Utilidoors would be temporarily closed and given a major refurbishment, with new tunneling being added going to all four parks and a new centralized resources hub outside of the parks. All delivieries, staff parking, etc would be relocated there with a peoplemover line being added to the new tunnels for improved transport of goods and cast members.
- New solar farms and battery banks would be added, with the aim of making the whole place entirely carbon neutral.
- Car parking would be made free for electric vehicles
- Busses would be slowly phased out and be replaced with the new and improved monorail line. For places that it's impractical to get the monorail to, either a peoplemover or gondala system would be added.
That's all I've got for now!