Help me. I'm over my head!!!

It really depends on how comfortable you want to be but remember the more items you take the heavier your bike will be.  You will probably want something to change into at the end of the day, unless you plan on walking around in your cycling clothes.  I would take either very lightweight shoes or flip-flops for your feet.

You could carry everything in a rucksack, although over this kind of distance I wouldn't want to as it would put a strain on your shoulders and neck.  The other option is a bar bag and or pannier set.  You can buy panniers that connect to your seatpost, so are suitable for road bikes.  On multi-day trips that I have done I have used a bar bag like this and a this pannier set.  I'd have thought you would be able to get everything into the bar bag for a two day ride.

The key is to travel as light as possible.  The two bags I have linked to are all I have ever used, even for three week cycle tours (unsupported).

My kit list for this would be:

• The cycle clothes you are wearing
• Lightweight rain jacket
• Multitool
• Frame pump
• Spare inner tube
• Two water bottles
• Energy bars (or similar) - buy more as you need them
• Credit card/money
• Flip-flops
• Maps/GPS (if paper copies of maps cut them right down)
• Toothbrush/toothpaste
• Lightweight clothes to wear in the evening
• Phone