We have stayed at both the AVI and the Riverside. I like the huge sites at the AVI, they run you 5 bucks a night more then the regular sites. Don't know about the TV cable because we have Satillite. The wifi is good and comes with the cost of the stay. Also, if you have pets, it's a lot better for walking them then the Riverside.
We also have stayed at the Riverside. They usually have a special going for 99 bucks a week and this gives you two breakfast buffets and two lunch or dinner buffets. (includes the Friday seafood buffet) I figured after the free buffet tickets it cost us around 46 bucks for 7 nights, not too shabby. There is one drawback to this, they might try to stick you in what I call the cheap seats. These are just west of the checkin and you are really, really close to your neighbor. They have shuttles to and from the Casino. They also have fenced dog runs, as does the AVI.
If the Riverside tries to stick me in the Cheap Seats I walk out and head to the AVI. Also, at the AVI you can purchase fireworks and set them across the river at a designated area. Usually get a good fireworks show each night. The AVI is KOA, but will also give Military Discounts.