We have spent a couple weeks at Desert Shadows, and I don't recommend it. Lots of freeway noise, and sort of a run down park model park.
We have stayed at Sunflower a couple of times and it is very nice. Lots of activities. The only negative is that you have to deal with the Bell Road/Sun City traffic everytime you come/go.
Our favorite on that side of town is Paradise RV Resort in Sun City. We spent two months there this year, and have just taken an annual space there. Lots of activities, great people. As of last week, there are still a few spaces available for the winter season, but they book fast. Not sure about Wifi, but don't think so. Mostly parkmodels, and they just added Quest DSL, but you must have it hooked up. We use our Verizon wireless aircard, so didn't need a land line. However, they have a nice computer room available.
Happy Trails is waaaaaay on the west side of town and and a good long drive along congested Bell Rd. to get anywhere. But it does have a golf course and is very nice.
Keep us posted on your final destination...