Burma, (which is aso called Myanmar nowadays), has lots of different treks you can do, and several really impressive peaks (like Hkakabo Razi, which is 5,881 m high), but generally they are in very remote regions which are extremely difficult to get to. Nat Ma Taung, which is accessible from Bagan (orPagan), is an excellent option for a serious trek during your trip to Burma.
This week long trek is a good option if you are looking for something to follow up the unmissable visit to Bagan. After you have visited this incredible archaeological site and seen its marvels of human architecture, why not continue on by exploring the landscape of Burmese nature and the western summits ? Because this isn't just an also-ran option, and the week you'll spend travelling towards Nat Ma Taung is bound to please you just as much.
But, because of time constraints, my advice is to do at least part of the journey in a 4x4. The walk is at least 5 days long, which seems enough to me to really enjoy the scenery! So, charter a jeep to get to the Mount Victoria National Park. When you leave Bagan you need to go back to Chauk, cross the Irrawaddy river and climb the hills on the other side, taking you inside Chin State. It's a really interesting journey and you'll go through villages and countryside that show all the particularities of this remote area. Like often in Burma, you can meet the local ethnic groups who live there (here they are famous for the women's facial tattoos).
It begins after Kanpetlet and I suggest you find a guide and make sure you have a jeep for your return journey before you get to this last village, if you haven't done so already. The path goes directly into the national park, a space where nature is preserved, so all along the way you can enjoy the wealth of Burmese nature, especially the endemic flora and fauna. The black orchid, although rare, is far and away the star of the show.
The route is punctuated by little villages, where you can stop the night and probably get supplies. The places to stay are a bit rudimentary, and you will usually have a choice between a local inn or a humble, but superb, bamboo hut (you couldn't get more authentic!).
You arrive at the summit after a final climb of about 10 kilometres, from where you can enjoy the pagoda which is not far from the top as well as, obviously, a staggering panorama. From there its a downwards trek of about 7 km to the point where a jeep can pick you up. You should know that this is the journey that is most often suggested by the trekking agencies and which I advise you take because, if you don't, you need lots of organisation, forethought (where you are going to stay overnight is very important) and a few days longer to get down to the first village on foot, or have to take the chance that you might find a jeep available on these wild country roads!