JRT is it the right breed for me?

Reading the comments and posts have been very helpful on deciding if I want a JRT as a pet. My question though is

What kind of activities do you do to keep the dog busy?
ie
playing fetch
running around the yard
going for walks
Are they afraid of water?

I read in a faq somewhere that these dogs tunnel. Yet now one on this site seems to have had major problems with this. My house is huge enough that if the dog wants to run all over he has enough space also the house sits on 1.5 acres of property. More than enough space. And fenced in.

When I let him out do I need to be concerned about the "tunneling" issue?

-John Cipolla