Relocating to Brazil - lived there years ago

My passport is American but my alma is Brazilian.
I've and worked in Rio and Sao Paulo.
I plan on arriving in the first quarter of 2017.
I don't want to buy property; just rent, relax and enjoy life.
My first choice city is Rio but I'm going to look at other locations.
Is the social/political climate still good an old guy?

Its aways good, if you have "loads of money", and not so good if you dont,

Personally, I'd go for a smaller city rather than Rio or Sao Paulo.  I can't relax and enjoy life in a big city...too many people, too much crime, I would feel lost in the crowd. 
Campinas?  Limeira?  Porto Alegre even seemed nice.  I know there are many more...

Goiania is beautiful but far from the beach.

try "Cabo Frio"  in the state of rio, about an hour drive from the city of  rio de janeiro