My family & I loved San Francisco but only had 1 full day to visit on our way to Yosemite. We walked along the waterfront & Lombard St., toured Alcatraz, & rode the cable car. I could easily spend a few more days there.
Sedona is still one of our favorites. We did the Pink Jeep tour and took the Grand Canyon Railroad from Williams, AZ to the GC. It was cute but very time consuming for the amount of actual time spent at the GC. I would go by car next time and be able to stay later at GC or if you really want to try the railroad, get a hotel in GC so you don't have to go back same day.
We flew into Vegas so that we could tour Hoover Dam on the way to Sedona. A pp said it's a 3 hr drive from LAS to Sedona. I was thinking it was more like 5 hrs so I checked and Google maps says 4 hrs. 18 mins. We stopped on the way to eat so that's where I was thinking 5 hrs. We stayed 1 night in Vegas because ds, now 14, was only 6 when we went and it was our kids' first flight that was longer than the 2 hrs that they're used to with flying to MCO. I worried that the 5-6 hr flight then a long drive might just be waaay too much sitting still for him. I wouldn't recommend the Vegas stay. I knew it's not exactly a family destination but wasn't prepared for the "business" cards that litter the streets showing topless women offering their services. Also men standing along the curb wearing a t-shirt printed on the front, "We'll get a girl to your room in 20 mins."

Our plan was to just "see the strip" fountains at Caesars Palace, etc. We saw a Cirque show but we were so tired by then we all fell asleep. YMMV.
I would definitely recommend Hoover Dam though. We did the engineering tour and found it very interesting.
We had a week in Sedona because at the time we owned a weeks-based TS and could trade. The time flew quickly but 1 week felt like a good amount of time there. We planned some down time to relax by the pool & just walk around shopping uptown. I'm not sure how their weather is in April if pool time is even a consideration.
I think what we loved so much about Sedona is that the beauty is all around you. Behind the Walgreens, on the way to the gas station, everywhere you look. I'm envious of the locals who can see this every day.

The GC is not a place you just stumble upon. You have to follow the signs for it, get out of your car, etc. It's hard to explain but both places are definitely something I'd recommend. Very family friendly.
We also enjoyed Niagara Falls (Embassy Suites Fallsview) but it would drop to the 50s at night in late June so I'd check April temps before planning to go there. Williamsburg is great too. We love Busch Gardens but love their water park even more so if given the choice I'd go there in summer. Also it's around 45 min drive to VA Beach so another reason to visit in summer.
jmho.

Have fun planning! Enjoy the ages your kids are now. Teen years will come in a blink along with that "know it all" highly-opinionated attitude. Sometimes it puts a strain on travelling.
