The Searchlight Airport has two cased with 400 and 470 in them. Just thought it may be of use to those in need of more caps.

There's also 2 cases in the Black Mountain mutant camp. They are in a large shelter. One with 500 and one with 200+. There's also a mini gun there. Just gotta get past the mutants. I was gonna make a hit and run on it, but I eventually got killed on my way out.

Also relatively easy:
In the REPCONN HQ on the top floor, there's a briefcase with 200 pre-war money.
Depending on barter skill it can net you quite some money.

Or you can fatten your wallet at the blackjack tables. Just try not to get kicked out. :wink_smile:

In the mining camp near the beginning of the game, the office upstairs has a safe and two trunks for a total of ~700 caps.

Or you can gamble at the strip, I made 21,000 before getting kicked, now thats just one casino, so yeah you can easily be set for life there.