Im running with an i5/980ti/16gig ram rig, just (hopefully) successfully installed TTW after downloading FO3 and NV off of steam. Using MO, everything seems to be in order (don't know if TTW should go before or after DLC plugins in load order) but when I start a new game I am taken straight to the NV intro rather than FO3 as I have read it should be.
I did not check the optional startup box on installation, and my start screen says 'Tale of Two Wastelands'. I'm running through the 4gb version of NVSE.