The problem you have is that from MCO to BKK, the shortest trip are via Europe, for under 23 hours total traveling time; while coming back, it is faster to fly across the Pacific (total time again under 23 hrs vs 27 via Europe). And it is very hard if not impossible to find cheap economy airfare that let you fly eastbound both ways. Meaning you have to choose between shorter flight going or coming back.

If you decide to buy business class tickets, then it is possible to construct a round-the-world fare using multiple carriers and just go eastbound both ways.

As for upgrades, you mean going from coach to business. What FF miles do you have and how many? Keep in mind that depending on the FF program and carrier, you may have to buy a more expensive coach ticket in order to use mileage upgrades and/or pay a substantial co-pay.

Do your homework carefully before buying your ticket if you plan to use miles to upgrade.

Going half way around the world is inevitably going to be a long trip up in the air. The time on the ground, waiting to change planes, can be dealt with by minimizing the number of stops. For instance, Lufthansa will take you from Orlando to Frankfurt and then on to Bangkok, while other operators from Orlando require two or more stops.
For research, the Internet is crowded with on-line travel agencies which will offer you itineraries: Orbitz, Expedia, Travelocity, Cheapoair, Hipmunk and many more. One place to start is www.Kayak.com which surveys many of these agencies. Once you see what airlines are available, you can buy from these agencies or go directly to the airline sites.
Since Orlando is not a major gateway, its international optons are limited. Try Miami, or other convenient big cities. Then check the specific airlines to see if they offer add-ons to Orlando with domestic partner airlines.

If you have the miles, upgrading to first or business class is the best possible way to use them, IMO.

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Vic's travels: http://my.flightmemory.com/vogilvie