I'll agree with Dex, the STP is an "easy" 200.
I agree...if you're planning to ride the STP in 1 day, it's best to train for mileage, not hills. There are rollers, so I've heard from plenty of first-timers who said (post-ride), "I thought you said it was flat?!!" Well, it is flat - for a double century in the Northwest! And, regardless whether it's 60 or 30 miles from the finish line, it's a long day in the saddle, so I usually kept myself motivated from the Lexington/Riverside park rest stop all the way in, with constant encouraging and incenting thoughts of [hot shower, cold beer, hot shower, cold beer, oh yeah!]...
(5x1-day here and whew! finally got it outta my system, so no mas!)