Last year we stayed in a fantastic airbnb in Portalnd for $160/night after taxes, fees, etc. I would steer clear of Old Orchard Beach. The accommodations seemed pretty dated and were extremely overpriced due to the race. Portland is a much cooler place to stay anyways. It's a bit of a drive but worth it for the restaurants, post race brewery visits, and all around great vibes the city has to offer. If you're looking for some recommendations shoot me a PM and I can give some pointers based on our trip.