Everything you mention is a factor in the FCS playoffs. Been there, done that. The FCS makes it work. Yes, fans travel on a week's notice. It's the nature of the beast.
In the FCS playoffs, typically the higher seed hosts. If that means 31,000 BSU fans in Bronco stadium or 101,000 Tide fans in Bryant-Denny to watch a BSU/Alabama quarter-final game, so be it. I'm positive Bronco stadium would sell out for such an event. Are you suggesting there wouldn't be a full house in Tuscaloosa for a playoff game?????
The semi-final games and championship can be held in regional destinations, if that's deemed to be more desirable. There can even be an off week between the quarter-final and semi-final games and another off week between the semi-final and championship games if need be. The playoffs would just need to start at the conclusion of the regular season. It already takes about 5 weeks from the conclusion of the regular season til the BCS championship game as it is. Do away with 1 regular season game, if need be. There's not a logistics issue that can't be solved if college football ever truly wants to decide a national champion. It's not rocket science. The FCS has proven that for many years running.
16 teams in a playoff means that 15 of 16 teams end their season and possibly college career on a loss. With 35 bowl games, 35 teams end their seasons with a victory including 8 of the top 16 teams. That is nice for the fans and the amateur athletes to end on a winning game.
So if boise State has zero losses and Bama has one and is the lowest seed, the game will be played at at Boise and I guess Bama will only get 5000 of 30,000 total available tickets? That is not counting the 5000 or more tickets the sponsors and TV stations will get. Perhaps Boise fans get 20,000, bama 5000, and sponsors 5000 tickets? The total number of tickets to a playoff game would be less than the attendance of the lowest attended SEC regular season game, and that is good? No way is that fair to the fans who can't attend or the players who don't get to play a huge game in front of 80,000 to 100,000 screaming fans. Some hgh school games in Texas have attendance approaching or exceeding 30,000.
Of course they could do it, but would it be better? Not 16 or even 8teams in my opinion would be good for college football. I say take the top 4 and that is it. Play one quarter final game in the Sugar Bowl and one in the Orange Bowl. Let the winners play for it all in the Rose Bowl. That only adds one game to the top 2 teams and keeps the current bowl system in effect for the other 32 bowls.
If after 13 games you can't be ranked one of the top 4, you don't deserve a shot at the national championship. There will always be an argument that 5th place was cheated just like 8 teams will have the 9th place team feeling they deserved a shot, and just like the 17th placed team in a 16 tournament would feel slighted. Be good enough to make top 4 or enjoy your bowl game and don't worry about the national championship.
One big game or 2 will draw the fans. Having to travel all over the US to watch your team play week after week in post season action will dilute the fan base. I went to the Sugar Bowl and SEC game in 2008-2009. I went to the National Championship game in 2010. I might go to a bowl this year depending on where it is. It is not worth the expense or time off work to personally go to Miami or Pasadena after making 2 bowl games in a row. I will go to the SEC Championship if we make it. If we go to Arizona for the national championship game I will be there. Other than that I have made 7 home games and 2 away games this year already, and 2 bowls and one SEC Championship in the last 2 years. I am done. If we were undefeated and there was a playoff of 16 teams I would not try to make all 4 playoff games unless they were all in Tuscaloosa, in fact if I made one playoff game it would of course be the finals. Unless your kid plays on the team few would attend all 4 playoff games spread all around the country.
Too many games reduces the importance of each game. Make it top 4 and you get the excitement of the NCAA final 4 without wearing the fans and players out with too many additional games and too much travel and exense.
I know you think the FCS has been great but the facts are the facts. the attendance at the FCS games has been in a steady decline for the last several years. In 1992 there were 31,304 in attendance, in 1993 there were 29,200, in 1994 there were 27,674, in 1995 there were 32,000, in 1996 there were 30,053, in 1997 there were 14,771. there were a couple of years where the attendance reached 20,000 in the 2000's, but most were less than 20,000 with the 2001 and 2002 games having a whopping 12,000 fans in attendance.
The attendance for the 2009 FCS championship game was only 14,328 and it was played in Chatanooga which is a short drive for Appalachian State who were defending champs. the top 10 highs school attendance records in Texas are 36,000 to 50,000 (
http://www.txprepsfootball.com/history.html ) Alabama had 90,000 show up for the spring game which is a glorified practice. I don't think many true football fans would consider attendance of 14,328 for the FCS national championship game a success.