If you want to save money (and possibly stay in a safer neighborhood than Pioneer Sq), don't stay DT. Just stay somewhere close to link light rail.

Also, ditch the RV. You'll have more fun and save money again with simple tent camping.

BUT keep in mind many ppl have made reservations waaaaay back in March in ONP proper, so finding sites might be difficult. Unless we get wildfire smoke like last summer in August which can reach even into wilderness areas and cause ppl to cancel. OR you could try the ocean beaches which don't have limits.

If the area you want to camp inside the park is booked up, keep in mind it is surrounded by National Forest land which is first come, first serve.