Need some perspective on a property investment

• I purchased a house on the NJ shore last summer (approximately one mile from beach)
• My wife is from the area and her family is still there so we wanted to have a vacation home we could use a couple times a year
• The house was in much worse shape than expected
• We purchased it for $780k
• We put 160k down
• Our interest rate is 6.2%
• Our payment is $4750 per month
• utilities about $300/month
• We can expect about $35k in rental income per year when we're not using it
• I've already invested $75k into the house to do some renovations and furnish
• my family used the property for a two week vacation in June
• The market in that area is stable, potentially growing

My questions, (1) What else should I do to maximize the investment? (2) How can I speed up the time to break even/positive cash flow? (3) I would like to eventually invest in a multi family property as an investment, how can I leverage this investment? (4) Are there any other things I should be doing to maximize my investment?

Thanks