I haven't played through the main game completely yet. Im about as far as reaching new vegas, meeting that Yes Man robot and then working with the Enclave for a bit. I've played through the first three DLCs and then took an extended break. I'm thinking about finishing Fallout: New Vegas but I'm not sure if I should finish the main plot first or play though the 4th DLC, The Lonesome Road first. From the description in the wikia it sounds like I should finish the main game story line first before moving on to this last DLC. Any advice for those who have finished all of it?

Thank you kindly

If you finish the main game storyline, you will be unable to complete Lonesome Road, as the game will end.

So you should do Lonesome Road xP

-Nukeknockout

Ah ok, thanks.

The Main Quest leads to the End, the End leads to the Void, there is no return from the Void.
Do the DLCs before completeing the main quest, or you could do the main quest up until the warning sign and then head to the DLC.