We lived in Rapid City for a few years and go back often. While we were there Jul and August were the only months you could depend on being warm so take a coat. When you go to the Badlands you might want to stop at Wall, a complete tourist trap but worth a stop and they have RV parking. Another tourist trap is Deadwood, was really an interesting place until they allowed the casinos to take over. But still worth a look. Crazy horse has become very commercial but a must see, they do allow dogs on patio but not inside. You won't have any problem finding things to do.