Here are 2 listings I found online...I believe we stayed at the Fairview Park in late summer of 1997. The one Chickadee mentioned is probably Sandy Riverfront RV...it has info in the link at the bottom of his post...
Portland Fairview RV Park
Troutdale, OR, phone: (503) 661-1047
Rolling Hills Mobile Terrace & RV Park
Troutdale, OR, phone: (503) 666-7282
Here are two others listed...whatever you do... you should enjoy your stay...it is gorgeous country in the gorge area!
MM