Jersey Shore - first time investment

[Jean Paul Valley]

Wondering if anyone caN share their experience on vacation home rentals, specifically on the Shore, but any advice will do.

My background is that I own one rental home. Currently, I am researching the market for a second rental home. My preliminary plan is as follows:

build new home for roughly 600-650k within 2 blocks of shore.
rent at weekly for 2,500-3,500
drop down significantly for off season.
Some questions:
financing - is 30% down the norm for such properties? anyone know of scenarion where I can get away with 20%.
Off season - my concern is putting so much pressure on the summer months to make up the mortgage for the year. Given the shore locaiton, how unlikely is it that I get any off season tenants.
Rental agencies - im 2hrs from the shore so it may be best to use an agency to rent this out. How much do agencies eat into profit?
thanks for any and all advice.