We stayed at the Three Rivers Resort on 110 outside of forks, they have like only 3 full hook up sites so make a reservation asap. Its tight but I managed to squeeze my 30 footer in one. We enjoyed our week stay. Its a gas station/convenience store/restaurant and guided fishing tour place so it can be busy at times. Right across the road is Riverview RV park and Storage. It has a bit more room but has no trees at all unlike Three Rivers, which has a lot of trees.
Towards La Push is the Quileute Oceanside Resort. It looked VERY nice and would suit your needs nicely.
If you absolutely have to stay in the town of Forks then there is Forks 101 RV Park. It has new owners I believe and they did a lot of work on it and it is nice now too. Used to be quite run down.
Google search these and give them a call to be certain they have full hook ups and that they will suit your needs. Good luck and enjoy your trip.