If you stick to the $1/2 NL tables, you won't have to worry much about the Vegas "locals" taking your money. The action at the MGM is always good, but it's pretty far from the Venetian. The Wynn has a great room and the low limit NL games there are always good. They allow you to buy in for as much as you want. Some poker rooms limit the buyin to $100 or $200, but not at the Wynn.

The Venetian is a very comfortable room, but you'll find a better class of player trying to take your money (local pros).

Harrahs is also close - last time I played there they only allowed short buys and the half the table had no idea how to play poker. Crazy action.

You'll basically have fun at any $1/2 NL table.  If you're not and people are not laughing and chatting and having a good time, then just find another table.  That's what I do, life is too short.