Hmm, if you're heading to Oasis then you'll need to head through Central first, which is a good place to train due to the large quantity of trainers. And if you're worried about getting lost, then you can always pay the Ironwall Mercenaries to lead you through safely. Of course, until you're a Rank 2 trainer you're required to use the Ironwalls, since its considered too dangerous a location.
If you're able to go it alone, travel with a partner and make liberal use of your pokegear's map to avoid getting lost. The journey can be bad, but if you can avoid the stronger wild pokemon and don't get stuck in a sandstorm, you should be fine. The worst part is that all of the established paths get destroyed every time a sandstorm comes through, meaning every traveler has to find their own way. If you're worried however, the Mercenaries are a bit expensive, but will get you there safely.