finances

i am heading from the US to Australia in a few month for a year or more. I am wondering what kind of credit cards to get to maintain my credit and rank up points for flights. which cards are the easiest to use especially when it comes to contacting them because i am not planning on keeping my US number. Just how to go about finances in general when traveling abroad. i am going to get a bank account in Australia so that will be easy but more so wondering over maintaining my credit and bringing over my money from the US to Aussie