Full disclosure: My primary business sells 2-4 unit rental properties in the midwest to out of state investors, so take what I'm saying with a grain of salt.

Detroit Salt mine industry, one of the oldest industries in Detroit before the automobile industry. 

The salt water/air makes every wear out faster.Mike

Cons: TAXES (holy cow taxes are high on the cape), high cost property (median is now around $650k I believe, expect to pay closer to $1.5M minimum or much more for the more desirable locations such as on the waterfront), relatively short season with summer being the time when you’d make the bulk of your earnings (although it’s less seasonal than you might think and units will rent relatively well all the way up through Christmas before demand finally does drop off a cliff), high utility costs (don’t forget to factor in the cost for AC at a beach house, with doors opening and closing all day, in a region with high cost/kWh for electricity, also expensive to heat in winter), hard to find labor (major shortage of cleaners, tradespeople, etc on the cape currently), high property maintenance costs (beach houses take a beating: sand, salt, big parties, hurricanes, tough weather, long winters, etc. and expect to pay a premium for both labor and materials on the cape), HOAs (high fees, rental restrictions), traffic, taxes, and taxes.

I obviously don't live in Washington and the concept of a locale telling me I can or cut down a tree is a little foreign to me so take what I say worth a grain of salt.