Mod:Tale of Two Wastelands

Tale of Two Wastelands is a total conversion project that seamlessly merges Fallout 3 and its DLC into Fallout: New Vegas, allowing both games to be played in a single playthrough. It upgrades Fallout 3's mechanics to those of FNV, while balancing both games to feel like you're playing one full game (instead of two different games using the same character).

New Vegas mechanics like companion wheel, companion perks, weapon mods, crafting, recipes, harvestable plants, and poisons have been added to the DC wasteland items, NPCs, and world.

TTW also restores some unused content, fixes hundreds of thousands of bugs, add some items, changes the level cap from level 50 to 60, alters the FO3 bobbleheads to give mini perks (since it's already too easy to max SPECIAL and Skills in TTW), and more.

TTW isn't just FO3 in FNV. It has become a unique game, with it's own balance, fixes, changes, additions and other unique things that differentiates it from both FO3 and FNV.