Seven weeks is tight but still doable and you could cut mileage in a number of places along the way.
I really liked the TA, but if you want a shorter more direct route you can always:
- Plan your own route.
- Do the Southern Tier.
- Follow one of the fast crossing routes used by races (like RAAM) or tour companies who specialize in fast crossings
Personally I think you are missing out if you focus on too much on "the ultimate goal of crossing the country" at the expense of seeing the sights and meeting the people, but different strokes.
Another option might be to do half of the TA this year and half next.