Doggy Door?

Question
I have a ridiculously well behaved JRT puppy (7 months).  
Yet I have been reading that they can turn on you in a
second! Something that I would like to think he would never
do, as he follows me everywhere, and does everything I do,
and in my eyes is an angel. HA!  I read from a professional
website that  one woman has a JRT who is content being in a
'dog-proofed' room all day while she is at work.  I have a
room in my house that I could use for this same purpose and  
I was going to install a dog door in the room to the back
yard.  Should JRT's be left (with the option to be) outside
unsupervised for the day?  I let him out in the afternoons
all the time for 20-30 mins and he seems to do fine. Right
now he is in a crate while I am at work.  Let me know what
you think about installing the doggy door.

Answer
Hi Whitney,

As long as your back yard is very securely fenced in, he should be fine. Make sure that he has a collar and name tag on JUST IN CASE he should be bored and dig under the fence or scales it and gets out.(it's been known to happen!).
Anything is better than being in a crate all day. Even if you don't put a doggie door in, the room is a great idea. They need lots of exercise and relief from boredom or can become destructive; leave KONGS, toys, balls, treats, rawhides and other safe toys for him to play with while you are away. Some people even leave a TV on Animal Planet for them (seriouosly!).  
He sounds like a great dog, good luck with him!