Ok,  This is what I want to do.  I only stay in my trailer a few times a year, at the fall futurity's.  I would like to add a hookup for a T.V and a small space heater.  I went to an R.V dealer and he set me up with the hook-up that goes thru my trailer. What side does everyone usually put this on?  I have a 2ft short wall.  

He also said that I didn't need the big black cord for no more than what I am going to run.  He told me to go to a hardware store and buy an extension cord.  Can I get by with that?  Thanks for any & all help with this.  By the way, I plan on insulating the inside with the materials that I have seen on this site.  Nothing fancy, just want to watch a little T.V. at night & keep warm.

Hi ... I have my power inlet mounted under the gooseneck.  They're protected from the weather and with the covers closed protected from road splash when traveling.

Extension cords: Wire size is directly related to length and amount of power used.  Heaters use a lot of juice.  If the campsite outlet is close to your parking spot a 50' cord willl do.

But if anything is in the way, 100 ' is better.  For a heater, I would recommend at least a 12 gauge cord. 

I have an air conditioner, The a/c compressor motor is sensitive to voltage drop.  So, I use  two(2) 50 foot 10 gauge cords.  10 gauge cords are very heavy, so if the outlet is close, I only use a single cord.  Otherwise, the two cords give me 100 feet to the power.

How may watts does that space heater draw, 750, 1000, 1250, 1500, 1750, 2000? How much does the TV draw?

A 42 inch plasma tv draws 400 watts.  Your heater and tv should be okay.  Remember to use the surge protector on the TV cord.  The heater doesn't need it and could create a voltage spike as it cycles.