I guess this really breaks down into three questions.

1) Whats the maximum driving distance, where you would still become a full time member of a gym.

Probably about 30 min. away, but I drive slowly.

2) What is the maximum distance you drive for an occasional indoor day climb.

Hmm...if it is not regular and offers something more interesting than usual, I guess an hour would be the absolute max driving time for indoor. 2 hours for outdoor.

3) Lets say your local gym was 20 minutes away. Would you drive 20 mins further to go to a significantly nicer gym over a close low quality gym.

Well the 40 minutes fits into my hour window, so I guess it would be a good chance I may frequent such a gym when outdoor climbing is not a possibility.

If you feel inclined give details, explain your answers. I'd love to hear exactly how you feel about this.