[thefro526]

If you're only going to show up to a competition with a drivetrain, then I'd suggest a few things.

-It needs to be reliable, any failure is going to make your machine completely useless. (Not to mention make your team look bad.)
-It should be able to cross the bump in the center of the field.
-It should be able to climb the bridge - even if it can't tip the bridge down itself.
-It shouldn't be full size, make it as small as reasonable, you'll have a shot of being picked just as a third machine on the bridge.

If you've got a little bit more time, and have achieved all of the above objectives then you could look into building a very simple and effective scoring device. I'd suggest something along the lines of a hopper on top of the robot that can hold three balls. Add a simple mechanism at the front or rear of the hopper to allow the balls to fall out of the hopper and into the lowest goal. If the hopper is human filled, it's incredibly simple to build and use and you'll be an excellent alliance partner since you can run 3 balls at a time to a more capable scorer.

If you can swing it, throw a bridge device on there too, it doesn't need to be over complicated just a basic arm to tip the bridge down enough for you to get onto.

None of those things are difficult and could be built with what comes in the KOP and stuff you can buy from Home Depot or Lowes or a similar store. IMO, the robot I described above, would be an excellent second pick for many alliances since it can play a very strategic role when paired with two other capable machines.

Feel free to PM me for further explanation.