I don't like to run my engines for less than 1 hour as I've heard that is bad (no time for temps to boil off condensation); so I use that as a guide. That ends up being about 250sm or so by road.
I am for grins...collecting information on GA vs Commercial for different trips. I'll write a short case study below.
Case Study:
Date: yesterday
Function: Business (sales) meeting
Time: 1pm
Place: Grand Rapids, MI
CRC Employees: 2 -- myself, and a salesman who is not 'allowed' to fly GA per his wife
Trip: Atlanta to KGRR and back to Atlanta in one day
Distance: About 540nm
Ready, Set, Go!
Me: I go about my normal morning routine and leave my house at the normal time
Him: He gets up at 5:30 to leave his house by 6am to beat the traffic to KATL to catch a 7:30am flight -- the only one available to make the meeting and not have to go in the night before.
Me: I get there at 12:30...the meeting is 15 minutes away
Him: He gets there about 10:30 and has to wait, and drool for the meeting time to arrive
Me: When the meeting is over, I hop in my airplane and take off for the 3 hour ride home.
Him: Worried and frantic, he panics because if he can't make the 4:40 flight he has to wait until 7pm-ish to take off. He asks if I can carry his projector so he doesn't have to open TWO bags at security. I grin and say, "Sure!"
Me: I land at LZU at 7:15pm...wondering which flight he got on. I am eating dinner with my family at 8.
Him: He lands at 8...he got on the 4:40 flight...which was late...and even then sat on the runway...in the middle row between two large people (standby). He gets home at 9.
We talked and laughed about it today and he said, "Yes, but if my flight wasn't delayed I would have beat you home." And that is true.
But I also said...if we had another meeting in Chicago he would have never been able to get there and I would.
This is the third such trip we have flown separately...and I beat him home from the other two (Bentonville, Arkansas), and yes, even Tuscon. Beating him home from Tuscon was an anomoly of airline 'equipment' problems and him having to drive to Phoenix because the travel agent screwed up his tickets.
He beat me to Tuscon however...but only because I had the luxury of leaving a few hours later than I had planned (which was about the time he left). I would have had about twice the flight time as he did. Come to think of it, Tuscon was a stretch. Nobody throw rocks, but I have to go to California in a week or two, and I'm going commercial...sigh...
Final thought:
His trip was on all the comfort of the CRJ (which is code-talk for metal-bar seats with 2mm thick leather covering them...in an even smaller and tighter layout than a 737). He sat next to guy in a suit who was talking to his wife, and overheard, "Sigh. Yes, another $1,000 ticket to ride in a CRJ).