I had MANY years of road riding before setting out on the TAT, and limited time off road, but luckily with some good riding companions and coaching was able to complete the complete TAT on a DRZ 400. I was prepared to go solo but luckily I was able to go w/ two other riders. While I might have made it by myself there were some areas where this might not have been wise for my ability. If solo my riding skills wouldn't have improved as much as they did with coaching from the two others. In my case having two others was a safety issue to and gave me the confidence to attack certain places more aggressively than if solo.
IMHO- a novice should be on a DR650 (it's a smallish bike) or smaller, like a DRZ400 or better yet the WR250.
See my link below.