I highly recommend AGAINST riding it home. Not only for the fact that you're a beginner and you are definitely not ready for highspeed riding (Don't wanna kill yourself before you get started!) but unless you can go about 40-50 mph without getting run over the whole way it's gonna be hard on the bike.
Assuming you pick one up with stock gearing there's no way you will want to go 70 on it for any period of time. (Red line is 74 mph!) Even 60 is quite hard on it, with stock gearing it's best under 50 mph. Plus if you buy used it may need some maintenance before being on the road anyway, plus it may not be road registered and such so you may get in trouble. I know the concept of riding the bike home is really cool, but in this situation it is not practical AT ALL.
The TW is best at what you want to use it for, exploring off road anywhere between 5-45 mph. You can regear it to run 50-65 on the road comfortably, but that kills some off road performance. And of course, if you can live with a maximum happy cruise of 45-50 mph you can use it on the road too, with stock gearing.
Bottom line, you would be a fool to ride it for 2-3 hours to get it home. However if it's like a 5-10 minute ride on backroads that's a different story, as long as the bike is mechanically alright go for it!