Welcome to the DIS.
Just back from POR in August.
This is a beautiful resort. I went with DD age 9 and DS age 6 and they both loved it there.
There are a lot of things for kids to do.
Make sure you go see the piano player, Bob Jackson, one night at the lounge. He is there Wed-Sat nites 7pm-12a. He has the kids in the audience (and the adults) participate in his act. My kids loved him. It was so much fun.
The grounds and pools are really nice there. You can get a life jacket for free at the marina for your son. My son used his to get around by himself and ride the slide (while Mom was in arm's reach of course). You can pool towels at the main pool, Old Man Island, but you need to take towels with you to the quiet pools.
The food court is great with lots of choices. We really liked the sitdown restaurant, Boatwrights, for breakfast.
There is bike rental, boat rental, and a playground and a fishing hole where you can rent cane poles for about $4 for 30 mins.
There is also a carriage ride around the resort.
We used the buses and thought the service was really good. I would recommend using another bus stop in the AM instead of the main South Depot bus stop. It was the last stop and was always the most crowded with people having to stand.
Bus stop order was: West: North: East : South.
As for renovations, they are being done at POFQ now and there was no evidence of any renovations at Riverside when we there. I think the plan is to shut down certain areas at a time. But it should not impact your stay.
I would be happy to answer any other questions.
Donna