What part of the coast are you thinking? Oregon's got a substantial coastline and it's different in Gold Beach than it is in Neskowin, which is different than it is in Lincoln City, which different than it is in Tillamook, which is different than it is in Seaside.
How many days are you out here? If you've got the time, you can see the coast, you can see temperate rain forests, you can see mountains, you can see small towns, you can see (liberal infested) big cities, you can see high desert, you can see national parks, you can see geologic formations that will take your breath away, you can see national historic monuments, etc, etc. There's no shortage of stuff to do or see here. I've lived here my whole life and in those 4+ decades I've not stayed at home. But there's still tons of shit I keep thinking "I've got to get around to seeing that" or "I should go there and do that."
One note, though I'd wager it's probably not warranted, the Oregon coast isn't what a lot of people picture when you say, "let's go to the beach." The ocean is not blue, nor is it really the temperature a lot of out of towners find conducive to swimming. Also, a lot of the coast has some pretty treacherous currents, rip tides, and undertows. What the Oregon coast does offer, however, is its own rugged beauty you will find in few other places.
Give us the amount of time you're planning on being here and what areas you're thinking of, and I guarantee you that this board can come up with more stuff to do than you can fit in your trip schedule.