Burbank to Denver
Ontario to Denver
Orange County to Denver

When I went into college, I had lived my entire life in the San Francisco Bay Area and I went to school at the University of Colorado. I flew SFO-DEN nonrev about 20+ times a year (10 round trips). And I ONLY get to fly on United (no Frontier), and I DON'T get jumpseat privledges. The four years I was in college, I NEVER had a problem. NEVER, EVER, NEVER EVER, NOT EVEN ONCE!!!

The first time was when I flew back to visit some friends this December 15th. Planned on staying until December 23nd. Then we had a major snowstorm that closed the airport for 3 days (20th, 21st, and 22nd). I didn't even try to get out on Saturday the 23rd (althought I probably could have). Woke up at 6am on the 24th, stood by for flights at:
6am to SFO
6:30 to LAX
7:20 to LAS
8:25 to SMF
8:40 to PHX

Got on the 8:40am flight to Phoenix. PAINLESS. The actual aircraft flew DEN-PHX-SFO. No getting off the airplane. No changing seat. PAINLESS.

Of all the nonrev flying I have done, hub to hub has been the easiest.
If you try to fly LAX-DEN and all the flights are full, you can connect to ANY city on the west coast. Here are some good options:
Drive to Burbank, then BUR-DEN
LAX-ONT-DEN
LAX-SNA-DEN
LAX-PHX-DEN
LAX-SAN-DEN
LAX-FAT-DEN
LAX-SBA-DEN
LAX-MRY-DEN
LAX-PSP-DEN
LAX-TUS-DEN
LAX-RNO-DEN
LAX-LAS-DEN
LAX-SFO-DEN
LAX-OAK-DEN
LAX-SJC-DEN
LAX-SMF-DEN
LAX-SLC-DEN
LAX-COS-DEN

And I am leaving out Oregon (PDX, EUG), Washington (SEA, Spokanne), Idaho (Boise), New Mexico (ABQ)...

Oh, lets not forget United's 3 class Boeing 777's flown on hub-hub routes. Have you ever sat in a United first class seat on a 3 class airpane. Most amazing seat I have ever seen on an aircraft.