TOPIC: Runs back to back

Is it a bad idea to have a run back to back with another? 2 friends of mine are new to true dungeon geon and want to do a run but the only one where all 3 of us can do a run ends right before one I'm already planning on running.

It depends. I like to keep at least 24 minutes between runs, but i do know people who run back-to-back.
Basically, you know you will miss half (or more) of your coach time. You should check in for both runs when you arrive for the first. Try to pre-arrange classes for second run (or be happy with whatever is left). And definitely have stats prepared so all the coach needs is to copy numbers and verify a few tokens. Also, let the others in second group know what you are doing so they can use coaching time before you arrive without worrying.

Also, if the second run is our run friday evening, i still have the other 2 tickets. You should transfer the 1 ticket to one of those friends and then i can transfer the other 2 to you.

Try to sign in for both runs at the same time. Then when run 1 is over, get your stuff from the epilogue area but save your treasure draws for later, and head right back into the coaching area for run 2.

So I do not have the ticket for the other run so I can't sign in for the other one. Dies it usually take the full 2 hours to get through the dungeon? And how long is the coaching time and is that included in the 2 hour time?

Yes, the run will take the full 2 hours to get through the dungeon(*). However, it will also usually take a few minutes after the two hours to collect treasure, completion
tokens, survivor badges, turn in your lights and lanyards, etc. If you are pressed for time to get to another run, let the rest of your party know, and politely request to get your treasure first, and let the epilogue attendant know as well (usually they hand out treasure alphabetically by class).

(*)There are some exceptions to taking the full 2 hours to complete the run. Most of the exceptions require you to still wind up waiting in line to get your completion and treasure tokens, or involve not getting your completion and treasure tokens.

You'll be in the coaching room until 24 minutes after the start time of your run. It is part of the 2 hours. You can usually enter the coaching room ahead of your start time, usually up to 30 minutes early. There are some occasions that is not true. In particular, at GenCon this year, one coaching room is being used for runs that start at :03 and :39, so there is less buffer time on those.