Hi

. . . . convert this to HDTV prior to burning a DVD . . .

If you literally mean a DVD then that is not possible.

HDTV is at least 1280*720 or 1920*1080  mp4 or mts format.   DVD is 720*480 or 720*576 mpg format dependin on your TV standard.  You can play DVD on HD TV however there may be quality issues with the upscaling.

If the video must be on DVD to play on a DVD player then in the DVD burn settings increase the video bitrate to the maximum possible consistent with getting the movie to fit on a DVD disc.

. . . . What options are there for exporting this movie project to play on a wide screen HDTV . . . 

A lot depends on the TV capabilities.

1. If you have a Blu-ray burner then burn Blu-ray format to BD disc (or DVD disc if the movie is less than 20 mins long) however this does mean that you need a Blu-ray player to play back in HD and the movie is playable anywhere you have a BD player..
    
2. If the HD TV can play video in mp4 format from a USB device or over a network, then export as HDTV in the appropriate resolution.
    
3. If the TV can play AVCHD then export as AVCHD transport stream, selecting the appropriate resolution.
    
4. In either case 2 or 3 - copy the exported file to memory stick and plug this into the TV.
    
5. If the TV can access the computer for playback over a network - then put the video in a folder on the computer which the TV can access.
    
6. If you have a Windows 8 computer or laptop and the TV is networked you can also play the mp4 or AVCHD file direct from the computer/laptop to the TV.

HTH

John