this here link is betterhttp://www.gta4.tv/100percent.php
it has a great, organised online checklist to get this ridiculous achievement--you can get all the info there instead of spending $20 on a guide. And you can track it all online with a password account--no printouts necessary.
CAUTION: i didnt realize til 1/2 way thru exactly what was required for this, and burned a bunch of hours because I missed a stranger early on.
ONE OPTION: first playthru strictly for fun, because its a great story. dont bother trying to get the collector achieves, because you'll have to do them again in the "Key" runthru.
Be smart and do Key to the City and the Liberty City Minute in the second (or first) run-thru in 20 or less hours.
I found the jumps very hard to find and to execute even with maps and walkthroughs, so be sure to save before making each jump attempt--sometimes you have to find a specific bike or car on each attempt, and that can really suck up the clock.