Hey guys, I was planning on installing TTW, but I have a few questions first.
Do I need a fresh install of NV and FO3?
How would I go about doing this if needed?
Do I need to delete my mods or is there a way I can keep them?

Thanks.

I don't think a fresh install of FO3 and NV is required. A friend of mine just installed it on his existing FONV game that had a lot of mods on it and it ran with no issues. .... Come to think of it, I had a lot of mods on my FONV and it ran fine for me as well...

If for some reason you do have to do a fresh install - and if you got it through, or registered it with steam - you can move the data directories and then have steam check the games cache. It will download a new data directory and all will be as it was initially.

Do you mean the data folders from the steam>steamapps>common paths?

yep. when I bring the games back to defaults I just move them to a new location. Good for backing up things just in case.

Though not required, I would recommend a clean install just to prevent any problems, then use Mod Organizer so that you can have different profiles like a TTW profile and maybe a DUST profile

Thanks for the help guys. And for Haxorus, I have no interest in running Dust or using MO, but thanks for the input and advice.