Rickair, as usual, hit many points dead on. However I'll add this:

I know gas and rental rates are going up, but that estimate is insane. If this is something you're considering, you might want to research some schools in an area where the cost of living is lower.

Also, despite being on the road a lot, I'm averaging 14 days off a month right now. I know it's better than average but how many office workers can claim anything close to that? Not to mention the fact that when I leave work, I leave. No project deadlines, no 80 hour work weeks. I dare say if I had children I'd spend more quality time with them and be more involved in their lives than I ever would with a "real" job.