I'm an owner at the Sheraton Mountain Vista. Quite frankly, in terms of size and layout, I think you'll be much happier with a 1 bedroom premium -- especially if it's more than just two people. That's what we have and think it's just about the right size.
WiFi throughout is new; when we were there in July, it was only in the lobby but was planned for the entire facility. The interior is nice with wide inside halls. Kitchens have pretty much everything you need to cook meals (we did every night) in terms of cookware and utensils. W/D are great to have, but small.
As to the Lakeside Terrace, it's an older property. Interestingly, if you stay there, you check in at the Sheraton Mountain Vista.
For more detail on the Sheraton Mountain Vista than you can likely get on the SPG site, try the Starwood Vacation Ownership site at
www.starwoodvo.com. It has floor plans and info of what is in each unit.