We stayed at the Three Rivers Casino in Florence Oregon in September of 2006 and were very happy with the facilities. There is a large lot in the rear of the casino that is nice and level. They have chains separating the sites. One side is marked for RV's larger than 30 feet and has very wide sites. The other side is for the smaller rigs but the site width is more than sufficient. There is no charge for the use of these sites.
The people at the Casino were very friendly. The greeter at the door said we could stay as long as we liked. We ate in the restaurant and were pleasantly surprised at the quality of the food. We aren't gamblers so can't comment on the gaming. We just stayed there to save money. We will definitely go back again. It is off the main drag so it was very quiet.