Thanks for the help (here and on PF forums). I got it working! here's what I did...

1. Hide everything but land in CC3 and save as bmp
2. Open as "Greyscale Image Surface" in Wilbur
3. Save as "Muse DTED Surface"
4. File > New > Binary > Select .dte file in FT

From the advice I've gotten it seems like I've skipped quite a few steps but I have a landmass in FT. Hopefully, my shortcut won't cause any problems down the road.