Furnace getting power, but heat/AC not kicking on. LED on board is not lighting up. Thinking the transformer is gone
Follow-up and answer:

Replacing the transformer resolved the issue of the board not getting power. Once the transformer was replaced I swapped in a new fuse and it started up. On a hunch I plugged in the old transformer again and fuse blew. So the transformer was definitely a problem. 

For anyone with a Trace XE90 looking to replace the transformer powering the control board: you will need to mount the transformer in a new location as the transformer's form factor is different from what original shipped in the furnace, still the same product but a new form factor.

This did not completely resolve my problem however, as now I am blowing a fuse whenever I make a call for heat. Next step is to pull everything involved in heat from the board and add one back at a time until the fuse blows.