I think the nature of the track defines how far I'm willing to travel. Comes down to Cost vs Enjoyment (and probability of)
If the track is great and weather cannot ruin it then I'm more likely to enjoy it more. The more I enjoy it the further I'm willing to travel.
I'd be happy travelling a couple of hours to a great track but probably wouldn't go to a crap one round the corner.
P.S. I think travelling thousands of miles to have the racing rained off is really taking the p1ss!