1. Unlikely there will be a seat open on a transcon for you to upgrade into but if there is, it's probably worth the $100 to upgrade although the point of a mileage run is to spend as little $$ as possible for your miles so this could potentially double your cpm if you got in on a great fare.

2. Slow internet if the free alaska-air.com service is any indication...the streaming entertainment is faster, but still freezes up and therefore isn't worth the $$ til they get that figured out (watch the free stuff and then you won't mind having to re-load the program every 5-7 minutes since it's free).

3. Unless it's international and you have customs to deal with, nobody is going to care about your baggage....people take domestic day trips (sometimes red eyes) all the time, not just mileage runners.

Have fun!