Well-Kept State Park Campground
I spent three nights (arrived Monday, departed Thursday) at this lovely campground about an hour from my house. The grounds are well-maintained with easy access to some hiking trails that are easy to moderate in difficulty. (If I were in better shape without 50+ years of knee problems, I'd rate all the trails as easy.)
The campsites are a short walk to the Dosewallips River, which is shallow and not very fast this time of year. It's a longer walk to the Hood Canal itself.
You're not going to have a private, quiet, pristine wilderness experience here. US 101 runs through the park next to the campground, and the logging trucks can be quite loud. There are lots of families -- meaning, kids running around and riding bikes -- and the campsites are close to one another without any privacy. But, highway traffic is pretty much nonexistent in the evening and night and the entire camp was pretty quiet by 9 pm every evening.
The camp is arranged in a bunch of loops. The first and last sites in each loop are preferable because of all the open space between the site and the road. The last site -- in my case, No. 20 -- is the best with an RV because the trailer will provide privacy from the adjacent campsite and there's a big space to other sites. (See the attached photo.)
T-Mobile was 2 bars of 4G LTE reception. I have a Pepwave cellular modem in my trailer and had virtually no problem streaming shows.