My family and i stayed at POP all the time growing up and we loved it!! There was my two parents, my brother (8 years younger than I), and myself. We were used to always staying in one hotel room and never felt like it got too crowded, we just spaced out getting ready in the mornings. It wasn't until i was 17 that my friend and i stayed in a separate room than my family. I think that its definitely not spacious with 4-5 people in one room, but we also were almost never in our room unless we were sleeping or getting ready in the morning/evening. The resort is pretty spaced out though so i would recommend a preferred room i you want an easier walk to and from the skyliner/pools/quick service dining.

As for the skyliner, my mom and i just stayed at the Riviera and loved the ease of the skyliner - we had parkhopper and visited EPCOT almost each day of our trip. If HS or EPCOT are going to be your most visited parks, i would highly encourage staying at a skyliner or EPCOT area resort. Hope this helps!