Dutchmen, the length would be approx. 5ft at max length. After I posted I was also thinking I should be able to find a wire brush with a good amount of length to it. I like the ideas. Figure brainstorming with a group is better than brainstorming by my self! :)
Ticki2, I agree that the best solution is to replace the tubing. I may be able to get to it with out removing the refrigerator. The back access isn't the issue, the two vents that are required from Dometic are there but there is a plywood base the refrigerator sits on top of. The drain tube has a hole cut out and when I feel around, there is a gap between the plywood base and the bottom plywood base the camper is frame on. In this gap there are a couple wires that are fed through along with this 3/8 tube. I have tried breaking apart the hard rubber seal in a different location and the easiest way will be to drill it. I could cut out a 2" hole above the current tube to see if I can't free it from the rubber seal.
Thanks for the tips so far, I'll keep it updated with what I end up doing. If anyone else has any suggestions, feel free to chime in! Likely will wait until the weekend to do the work. Lot's of hours have been put in to fixing this camper up. Thankfully it keeps snowing in MN so I don't have to feel bad about the hours I've put in!