See the stuff I posted above.
Try to squeeze more disney time. I assume you'll hit DCA as well and one day at each park isn't enough. If you can squeeze a third day, where you can park hop between the two, it should give you most of both parks without missing much.
Staying on Disney property is always special. Even if its only for a couple of days (plus the perks for hotel guests when visiting the park - like parcel drop off are a bonus), but it IS pricey no matter where you stay. I doubt you'd get much benefit out of it if it were only overnight.
USH is very different to USS. USH is a working studio with backlot and a lot of other stuff going on, whereas USS was just and always only about the rides. It's a very different park in my opinion, However if you like USS you will like it, you will enjoy it. 1 day will be sufficient provided you're picky about busy periods, or willing to pay a little extra for the premium experiences like fastpass etc.
SFMM is also jam packed with people most days. I've only ever done the park for a single day per visit, and never managed to get EVERYTHING done - even with a platinum flash pass (although it is doable depending on who is with you and what pace you keep up), but a single day is still an alright visit, even if you miss things (tip: prioritise your must do's, decide what you're ok with missing, and leave that until last - don't waste time criss crossing the park - take a logical path from one side to the other so you don't have to backtrack).
Knott's is great, and a day should be sufficient.
Vegas is worth the trip. Although it goes against the grain, don't book a hotel in advance. Walk-ups (in my experience) always seem to get a better price. the New York coaster isn't worth it unless you want the credit, but Circus Circus is worth a couple hours. You'll lose a lot of time driving to see the canyon - we found a tour that picked up at the hotel, took you to the airport, flew you to the western edge, and then choppered you down into the gorge before boarding a boat. Great value, lunch included, and just over half a day, while still having plenty of time to see, marvel, take photos etc.