I'm visiting Miami for the first time next weekend for a long weekend. I'll be staying at the Doubletree Downtown (points redemption).

I have a few questions.

1. Is it safe to walk around downtown on my own in the evening. I envisage going down to the area where the HRC appears to be for dinner/drinks.

2. I plan on spending a few hours at the beach. As I'll be on my own is it advisable to rent a sunbed and have a dip? Will my belongings be safe? Is there any part of the beach best for this?

I plan on doing an everglades airboat trip. Is there anything else I ought to do/see in Miami? Sports?

TIA.
G