My family is visiting Guangzhou in July.

1. Actually, I'm not sure whether if those major attractions can accept credit cards. Thus for your convenience, you'd better to exchange enough RMB Cash to pay the entrance tickets.
2. About the accommodation, you can stay at a hotel near the Beijing Road. Lido Hotel is recommended. It has comfortable environment and kind service. The price is CNY 300-400 per night. The surrounding transportation is convenient. And you can easily get to popular shopping centers and local restaurants. The exact location is No. 182 Beijing Road. Hope you like.