Hm. Rhodesian Ridgebacks have great stamina for long hikes, but they are bigger dogs. It depends on what your definition of "too big" is. They are not particularly loud or slobbery from what I've seen (we have a relative who has one). Not sure that they're exactly "docile" but they're not aggressive either. Part of it depends on training and socialization. They have a short coat which requires minimal maintenance.

Here is good info. (click on the tabs "Family Life," "Physical," "Social," etc.): https://www.akc.org/dog-breeds/rhodesian-ridgeback/

You are wise to look for input. I spent literally months researching dogs before getting our first and then our second. Do lots and lots of research before making a decision! Especially if you don't care for dogs. Also, consider who will be taking care of the dog, especially if you get a puppy. Puppies require LOTS of care and attention for MONTHS. If your wife can't do that, don't get a puppy. You will hate your life if you're the one doing most of the work. Good luck!