Your camping trip sounds like a great tradition. Here are a few ideas to consider:
1) Oregon Coast – Cape Lookout State Park: The Oregon Coast is an amazing place to visit any time of the year, and I think that Cape Lookout is extra special because you can hike out to the end of the cape. There are lots of campsites, including group sites and even yurts! There’s also beautiful hiking, delicious seafood (of course), and other coastal fun to be had.
2) Eastern Oregon – Hart Mountain: This is a bit of a drive, but there are hot springs, antelope, hiking, and it’s just gorgeous. There’s camping right by the hot springs — it’s primitive but spacious, and I believe it’s free (it was as of a couple years ago). The star-gazing is top-notch, especially from the warmth of the hot springs. There’s some good hiking, and it’s close to the Steens as well if you wanted to explore further east. If you really want to “get away,” Hart Mountain is the place to go.
3) Northeastern Oregon – Wallowa Lake: There’s a reason this area is called the Alps of Oregon. It’s unbelievably gorgeous. These mountains typically get less snow than the Cascades, so there will likely be more hiking trails that have melted out and are ready to go. There are lots of camping sites and a few group sites at Wallowa Lake State Park. You’re also close to wild and beautiful Hells Canyon area and the idyllic town of Joseph. If you and your friends like beer, I’d recommend a stop at Terminal Gravity in Enterprise on your way in or way out. 🙂
I hope this helps get you started!