I bought this for my 2 year old and she loves it. She is the youngest of five, ages 15 to 2, so I've been through my share of slides. I was a bit concerned that she would quickly outgrow it, but now that I see it, I think that we will be able to get two to three more years of use. I had some friends over that have a 15 month old and she was able to use the slide without difficulty. It was easy to put together. I have it in her room for now. The width and length seem to be no larger than a crib.
View Step2 Naturally Playful Lookout Treehouse
Really well made! It assembles in minutes (except for the periscope but we left that off till our daughter was closer to 2.) We got it when she was 15 months and it is still going string and is fun for 3+ yr olds. Great indoor exercise toy. Step 2 is usually made in the USA but you should double check if that is a criterion.
View Step2 Naturally Playful Lookout Treehouse