I am finally at a point where my only debt is my mortgage at 5.25% a second at below prime and $10,000 left on a massive student loan at 7%.

I would like to start investing and also considering purchasing a beach house for rental income.

My question is: Should I pay down my mortgage to refinance it at 3.25% (the value of my home is what I owe because of the market values.) and pay off my student loan. (I am not able to deduct the interest because of my income.) Or can I start investing in stock? I hope to retire in 15 years.

Second question would be on buying a rental property. This would put me back into debt but would allow me to fulfill a dream of owning a beach home.

Thank you in advance for any advise.