Anchor Down is about 45 minutes from Pigeon Forge, according to how bad the traffic is. River Plantation is also on the other side of Sevierville, so it's a rather long drive (through awful traffic during the season). It's always "the season" there.
We prefer Pine Mtn RV Park for it's location. It is at traffic light #6 and is about 2 blocks from the turn-off to Dollywood. It's also almost at the end of town closest to Gatlinburg and the GSMNP.
There is no PERFECT RV Park for everyone. It's according to what you want. Sites will run you in excess of $50/night at the least. This is one of the places that you get what you pay for, so be advised.