How do I switch from MultiBit to Bitcoin-QT? Okay, so I have seen the questions on how to go from Bitcoin Core to MultiBit, but I want to go the other way.

Really, I downloaded and started using the wrong wallet.  I wouldn't even mind MultiBit if it wasn't for that the default folder can't be moved (I dislike having a cluttered home folder) - I asked, and the location is hardcoded.  Considering I use the default clients for the altcoins, I'd rather go with Core.

I'd transfer my little funds to Bitcoin Core and suffer the fee, but I have less than the threshold (0.006 something).

Is there a way to make my wallet active in Bitcoin Core, preferably without tearing my hair out?  Or should I (groan) keep mining altcoins next winter (too hot out right now for my poor PC cranked up), build up my Bitcoin balance by exchange, then transfer wallets the easy way?

Details are appreciated.  Thanks.
As far as I can tell, BTC 0.006 is not below any relevant transaction limit. A couple weeks ago I bought a cup of coffee for BTC 0.0033 and it went through without problems.

You would probably pay a fee of BTC 0.0001 - less than 2% of your holdings, and about US $0.05 at today's prices. At US minimum wage that buys roughly 20 seconds of your time. You'll spend more time (= money) than that just reading any other answer, much less implementing it.

Short version - just pay the fee!

(Future generations reading this will no doubt, one way or the other, find it hilarious that someone could/would pay BTC 0.0033 for a cup of coffee!)