"The length of the trip is a bit ambitious, and that worries me. I'm riding 10 to 30 miles daily right now - not really enough, I know. I guess I'll have to ride more for a month. "

Hmmm, this is almost April & you're talking about May, right? This is a long way to go with a small amount of training. I did a 500 mile ride (7 days) and I trained for six months. Plus, I had been riding for several years before that. I was completely prepared for everything except for the 4-6 hours in a saddle every day -- owweee!

Can you/would you bail if it got to be too much?