Stayed at the end of 1st Street, just hotels and the promenade right there. Super quiet after sunset, no other people parked on the street. We slept great.

Seaside has plenty of free parking downtown/near the coast with no signs discouraging overnight parking. Stayed on this st for 2 nights no issues in my van. Wouldn’t rec for an RV. Bathrooms and trash cans by the prom/beach.