First, you have to make some new friends after your arrival in UB. It is the perfect place to get together a group of people to share costs for a trip into the wilderness. Use some of the online groups and discussion forums to find like-minded people to join the trip.
Most travelers hire a driver and a guide in Ulaanbaatar because it’s quite difficult to get around Mongolia by public transport. The train goes straight through Mongolia from south to north, and only major cities, provincial capitals, and a few towns are accessible by public bus.
Speed limits. Speed limit within Ulaanbaatar is 60km/hour. On the highways it is 80km/hour. Think like this way: average car speed is 30 km/hour on bumpy dirt road, and 80km/hour on highway. So, do expect to spend 5–6 hours in car per day. Be realistic and do not challenge the driver’s skills on the bumps of dirt roads and test your back and stomach unless you plan an absolutely sporting raid.
When you look at the map, note that only dirt roads are practically everywhere in Mongolia. Some of the asphalt roads are often worse than the dirt trails. After long drive, plan some time to spend by a lake or a river and relax for few more days (hiking, horse riding , fishing, and swimming).
If you’re easily to get car sick, prepare carsick medicine in advance. Like I mentioned, there’s no actual road to drive through in the Gobi Desert so the path will be extremely bumpy and you will most likely end up making a huge mess in the van or car.
In summer, don’t forget to bring insect repellent. At night in the ger, sometimes there are some unexpected visitors attacking you while you’re sleeping. That can be very annoying!
Take light clothing that can cover and protect you from the wind and the sun in the summer. However, you might want to take t-shirts and shorts with sandals. In the car might be ok. When trekking in Gobi Desert, if you wear sandal, shorts, you foot will just burn, climbing to the sand dune with sandals or riding horse with sandals and t-shirt are not good idea. So, better take light weight trekking shoes.
Going to the toilet might be a problem. In the wilderness there is not proper toilet to use. Although there is no privacy in the nature, but do we have choice. Bring something that helps you to digest, like a pill or yeast, whereas most of the time you’re eating meat and very less vegetables. There might be days that you can’t do the job.
If you can’t live without technology, Mongolia is not a place for you, unless you just stay in cities. Your phone is just to take photos and when the battery dies out, you can put your phone away, too. There’s no place for you to charge your phone in the nomad ger.
Do not exclude that you may have to shorten your route due to unforeseeable circumstances such as local weather conditions, medical quarantines, etc. or to modify it spontaneously in order to experience an exciting event on the road (a local naadam, traditional ceremony, wedding, etc). It is important to let your emotions thrill.
You will have to cross small villages in countryside on the road for food, drinks and fuel supply.
About gasoline. Regular 92 is most common available throughout the country, but gasoline quality in countryside especially in remote villages are not good quality. Fill up your tank in major cities and towns if possible. When you drive to the far western provinces of Uvs or Bayan-Ulgii, the far you go from Ulaanbaatar the price of gasoline will become more expensive.
For filling up the car, most places take credit card including Visa. Some don’t though so have cash as an option as well. Never rely on only one payment method.
Finally, travel with a local that can design the best suitable route according to your wishes and possibilities. Treat them nicely, make friend with them, they will also be nice and friendly to you.