CSR is my favorite of the moderate resorts but with young kids I'd go with CBR instead. The pool at CSR is nice, on the larger side for moderate pools, with one of the longest, fastest pool slides of any of the resorts and a fabulous hot tub. But unless your kids are exceptionally brave and good swimmers, a lot of that is probably wasted on them. CBR, on the other hand, has a zero-entry pool, water cannons on the fort, and a pirate-themed splash pad/water play area. It isn't just for little kids - the pool and slide are plenty big enough for older kids to love - but it has more to offer younger ones than CSR's feature pool.
I would, however, steer clear of the pirate rooms - Disney played that card perfectly, getting people to pay a premium price for the least-desirable location in the resort! - and seriously consider booking preferred to guarantee being close to the pool. The size of CBR is the main complaint we had about it, but we were foolish enough to book the then-new pirate rooms and got one of the most distant rooms in the furthest building from the resort's amenities. And that did put something of a damper on enjoying the resort amenities.