How many calories do you burn riding 500 miles?

Well, we head out tomorrow. I seriously hope my 100 miles of "training" is enough to cut it for this 500+ mile ride. 

Things I'm excited for:

Nature

Real camping

-not texas camping in a cabin...roughing it camping in tents and everything! Wahoo!! This is what I grew up on and I'm thrilled to be outdoors camping for a week.

Burning thousands of calories!

Getting this over so I can start training for my princess half!!!!

And then it poured

I woke up, ready to go. I grabbed my riding shorts, pulled out my cute, new jersey, grabbed my bike...CCLLLAAAAPPPP. The sound of thunder. I looked outside to see a downpour and the tv started blaring flash flood.

Ugh....

Soooooo annoying. I was completely set to go. My mind was in the right place, breakfast in my belly. 

That's just my luck I guess. 

I need motivation

Because riding 500 miles in 6 days is clearly not enough to make me train. 

To be anywhere ready I should be riding 100+ miles weekly...and I'm averaging 40. I just get bored. 

Houston isn't the most biker friendly area so I'm stuck riding the same trails over and over. Its repetitive. 

Any suggestions? What has helped you stay motivated and push you along on long runs or bike rides?